Release version 4.0 M2 (2022.0.0).

See #3937

.mvn/wrapper/maven-wrapper.properties

@@ -1,2 +1,2 @@
-#Tue Feb 22 13:55:00 CET 2022
-distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.4/apache-maven-3.8.4-bin.zip
+#Mon Oct 11 14:30:24 CEST 2021
+distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.3/apache-maven-3.8.3-bin.zip

CI.adoc

@@ -1,6 +1,6 @@
 = Continuous Integration
 
-image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2Fmaster&subject=Moore%20(master)[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/]
+image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2Fmain&subject=Moore%20(main)[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/]
 image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2F2.1.x&subject=Lovelace%20(2.1.x)[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/]
 image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2F1.10.x&subject=Ingalls%20(1.10.x)[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/]
 

CONTRIBUTING.adoc

@@ -1,3 +1,3 @@
 = Spring Data contribution guidelines
 
-You find the contribution guidelines for Spring Data projects https://github.com/spring-projects/spring-data-build/blob/master/CONTRIBUTING.adoc[here].
+You find the contribution guidelines for Spring Data projects https://github.com/spring-projects/spring-data-build/blob/main/CONTRIBUTING.adoc[here].

Jenkinsfile

@@ -9,7 +9,7 @@ pipeline {
 
 	triggers {
 		pollSCM 'H/10 * * * *'
-		upstream(upstreamProjects: "spring-data-commons/2.5.x", threshold: hudson.model.Result.SUCCESS)
+		upstream(upstreamProjects: "spring-data-commons/3.0.x", threshold: hudson.model.Result.SUCCESS)
 	}
 
 	options {
@@ -20,10 +20,10 @@ pipeline {
 	stages {
 		stage("Docker images") {
 			parallel {
-				stage('Publish JDK (main) + MongoDB 4.0') {
+				stage('Publish JDK (Java 17) + MongoDB 4.4') {
 					when {
 						anyOf {
-							changeset "ci/openjdk8-mongodb-4.0/**"
+							changeset "ci/openjdk17-mongodb-4.4/**"
 							changeset "ci/pipeline.properties"
 						}
 					}
@@ -32,17 +32,17 @@ pipeline {
 
 					steps {
 						script {
-							def image = docker.build("springci/spring-data-with-mongodb-4.0:${p['java.main.tag']}", "--build-arg BASE=${p['docker.java.main.image']} --build-arg MONGODB=${p['docker.mongodb.4.0.version']} ci/openjdk8-mongodb-4.0/")
+							def image = docker.build("springci/spring-data-with-mongodb-4.4:${p['java.main.tag']}", "--build-arg BASE=${p['docker.java.main.image']} --build-arg MONGODB=${p['docker.mongodb.4.4.version']} ci/openjdk17-mongodb-4.4/")
 							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 								image.push()
 							}
 						}
 					}
 				}
-				stage('Publish JDK (main) + MongoDB 4.4') {
+				stage('Publish JDK (Java 17) + MongoDB 5.0') {
 					when {
 						anyOf {
-							changeset "ci/openjdk8-mongodb-4.4/**"
+							changeset "ci/openjdk17-mongodb-5.0/**"
 							changeset "ci/pipeline.properties"
 						}
 					}
@@ -51,24 +51,7 @@ pipeline {
 
 					steps {
 						script {
-							def image = docker.build("springci/spring-data-with-mongodb-4.4:${p['java.main.tag']}", "--build-arg BASE=${p['docker.java.main.image']} --build-arg MONGODB=${p['docker.mongodb.4.4.version']} ci/openjdk8-mongodb-4.4/")
-							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
-								image.push()
-							}
-						}
-					}
-				}
-				stage('Publish JDK LTS + MongoDB 4.4') {
-					when {
-						changeset "ci/openjdk17-mongodb-4.4/**"
-						changeset "ci/pipeline.properties"
-					}
-					agent { label 'data' }
-					options { timeout(time: 30, unit: 'MINUTES') }
-
-					steps {
-						script {
-							def image = docker.build("springci/spring-data-with-mongodb-4.4:${p['java.lts.tag']}", "--build-arg BASE=${p['docker.java.lts.image']} --build-arg MONGODB=${p['docker.mongodb.4.4.version']} ci/openjdk17-mongodb-4.4/")
+							def image = docker.build("springci/spring-data-with-mongodb-5.0:${p['java.main.tag']}", "--build-arg BASE=${p['docker.java.main.image']} --build-arg MONGODB=${p['docker.mongodb.5.0.version']} ci/openjdk17-mongodb-5.0/")
 							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 								image.push()
 							}
@@ -78,10 +61,11 @@ pipeline {
 			}
 		}
 
-		stage("test: baseline (main)") {
+		stage("test: baseline (Java 17)") {
 			when {
+				beforeAgent(true)
 				anyOf {
-					branch '3.2.x'
+					branch(pattern: "main|(\\d\\.\\d\\.x)", comparator: "REGEXP")
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
@@ -95,7 +79,7 @@ pipeline {
 			steps {
 				script {
 					docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
-						docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.0:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
+						docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.4:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
 							sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
 							sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
 							sh 'sleep 10'
@@ -110,37 +94,15 @@ pipeline {
 
 		stage("Test other configurations") {
 			when {
+				beforeAgent(true)
 				allOf {
-					branch '3.2.x'
+					branch(pattern: "main|(\\d\\.\\d\\.x)", comparator: "REGEXP")
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
 			parallel {
-				stage("test: mongodb 4.4 (main)") {
-					agent {
-						label 'data'
-					}
-					options { timeout(time: 30, unit: 'MINUTES') }
-					environment {
-						ARTIFACTORY = credentials("${p['artifactory.credentials']}")
-					}
-					steps {
-						script {
-							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
-								docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.4:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
-									sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-									sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
-									sh 'sleep 10'
-									sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
-									sh 'sleep 15'
-									sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
-								}
-							}
-						}
-					}
-				}
 
-				stage("test: baseline (LTS)") {
+				stage("test: mongodb 5.0 (Java 17)") {
 					agent {
 						label 'data'
 					}
@@ -151,7 +113,7 @@ pipeline {
 					steps {
 						script {
 							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
-								docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.4:${p['java.lts.tag']}").inside(p['docker.java.inside.basic']) {
+								docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-5.0:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
 									sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
 									sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
 									sh 'sleep 10'
@@ -168,8 +130,9 @@ pipeline {
 
 		stage('Release to artifactory') {
 			when {
+				beforeAgent(true)
 				anyOf {
-					branch '3.2.x'
+					branch(pattern: "main|(\\d\\.\\d\\.x)", comparator: "REGEXP")
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
@@ -186,6 +149,7 @@ pipeline {
 				script {
 					docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 						docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.basic']) {
+							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -v'
 							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml -Pci,artifactory ' +
 									'-Dartifactory.server=https://repo.spring.io ' +
 									"-Dartifactory.username=${ARTIFACTORY_USR} " +

README.adoc

@@ -1,6 +1,6 @@
 image:https://spring.io/badges/spring-data-mongodb/ga.svg[Spring Data MongoDB,link=https://projects.spring.io/spring-data-mongodb#quick-start] image:https://spring.io/badges/spring-data-mongodb/snapshot.svg[Spring Data MongoDB,link=https://projects.spring.io/spring-data-mongodb#quick-start]
 
-= Spring Data MongoDB image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2Fmaster&subject=Build[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/] https://gitter.im/spring-projects/spring-data[image:https://badges.gitter.im/spring-projects/spring-data.svg[Gitter]]
+= Spring Data MongoDB image:https://jenkins.spring.io/buildStatus/icon?job=spring-data-mongodb%2Fmain&subject=Build[link=https://jenkins.spring.io/view/SpringData/job/spring-data-mongodb/] https://gitter.im/spring-projects/spring-data[image:https://badges.gitter.im/spring-projects/spring-data.svg[Gitter]]
 
 The primary goal of the https://projects.spring.io/spring-data[Spring Data] project is to make it easier to build Spring-powered applications that use new data access technologies such as non-relational databases, map-reduce frameworks, and cloud based data services.
 
@@ -8,10 +8,12 @@ The Spring Data MongoDB project aims to provide a familiar and consistent Spring
 The Spring Data MongoDB project provides integration with the MongoDB document database.
 Key functional areas of Spring Data MongoDB are a POJO centric model for interacting with a MongoDB `+Document+` and easily writing a repository style data access layer.
 
+[[code-of-conduct]]
 == Code of Conduct
 
 This project is governed by the https://github.com/spring-projects/.github/blob/e3cc2ff230d8f1dca06535aa6b5a4a23815861d4/CODE_OF_CONDUCT.md[Spring Code of Conduct]. By participating, you are expected to uphold this code of conduct. Please report unacceptable behavior to spring-code-of-conduct@pivotal.io.
 
+[[getting-started]]
 == Getting Started
 
 Here is a quick teaser of an application using Spring Data Repositories in Java:
@@ -59,6 +61,7 @@ class ApplicationConfig extends AbstractMongoClientConfiguration {
 }
 ----
 
+[[maven-configuration]]
 === Maven configuration
 
 Add the Maven dependency:
@@ -68,24 +71,25 @@ Add the Maven dependency:
 <dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-mongodb</artifactId>
-  <version>${version}.RELEASE</version>
+  <version>${version}</version>
 </dependency>
 ----
 
-If you'd rather like the latest snapshots of the upcoming major version, use our Maven snapshot repository and declare the appropriate dependency version.
+If you'd rather like the latest snapshots of the upcoming major version, use our Maven snapshot repository
+and declare the appropriate dependency version.
 
 [source,xml]
 ----
 <dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-mongodb</artifactId>
-  <version>${version}.BUILD-SNAPSHOT</version>
+  <version>${version}-SNAPSHOT</version>
 </dependency>
 
 <repository>
-  <id>spring-libs-snapshot</id>
+  <id>spring-snapshot</id>
   <name>Spring Snapshot Repository</name>
-  <url>https://repo.spring.io/libs-snapshot</url>
+  <url>https://repo.spring.io/snapshot</url>
 </repository>
 ----
 
@@ -98,7 +102,7 @@ Some of the changes affect the initial setup configuration as well as compile/ru
 
 .Changed XML Namespace Elements and Attributes:
 |===
-Element / Attribute | 2.x | 3.x
+| Element / Attribute | 2.x | 3.x
 
 | `<mongo:mongo-client />`
 | Used to create a `com.mongodb.MongoClient`
@@ -116,7 +120,7 @@ Use `<mongo:client-settings cluster-hosts="..." />` instead
 
 .Removed XML Namespace Elements and Attributes:
 |===
-Element / Attribute | Replacement in 3.x | Comment
+| Element / Attribute | Replacement in 3.x | Comment
 
 | `<mongo:db-factory mongo-ref="..." />`
 | `<mongo:db-factory mongo-client-ref="..." />`
@@ -133,7 +137,7 @@ Element / Attribute | Replacement in 3.x | Comment
 
 .New XML Namespace Elements and Attributes:
 |===
-Element | Comment
+| Element | Comment
 
 | `<mongo:db-factory mongo-client-ref="..." />`
 | Replacement for `<mongo:db-factory mongo-ref="..." />`
@@ -153,7 +157,7 @@ Element | Comment
 
 .Java API changes
 |===
-Type | Comment
+| Type | Comment
 
 | `MongoClientFactoryBean`
 | Creates `com.mongodb.client.MongoClient` instead of `com.mongodb.MongoClient` +
@@ -174,7 +178,7 @@ Uses `MongoClientSettings` instead of `MongoClientOptions`.
 
 .Removed Java API:
 |===
-2.x | Replacement in 3.x | Comment
+| 2.x | Replacement in 3.x | Comment
 
 | `MongoClientOptionsFactoryBean`
 | `MongoClientSettingsFactoryBean`
@@ -226,6 +230,7 @@ static class Config extends AbstractMongoClientConfiguration {
 ----
 ====
 
+[[getting-help]]
 == Getting Help
 
 Having trouble with Spring Data? We’d love to help!
@@ -239,6 +244,7 @@ If you are just starting out with Spring, try one of the https://spring.io/guide
 You can also chat with the community on https://gitter.im/spring-projects/spring-data[Gitter].
 * Report bugs with Spring Data MongoDB at https://github.com/spring-projects/spring-data-mongodb/issues[github.com/spring-projects/spring-data-mongodb/issues].
 
+[[reporting-issues]]
 == Reporting Issues
 
 Spring Data uses Github as issue tracking system to record bugs and feature requests.
@@ -249,10 +255,86 @@ If you want to raise an issue, please follow the recommendations below:
 * Please provide as much information as possible with the issue report, we like to know the version of Spring Data that you are using, the JVM version, Stacktrace, etc.
 * If you need to paste code, or include a stack trace use https://guides.github.com/features/mastering-markdown/[Markdown] code fences +++```+++.
 
+[[guides]]
+== Guides
+
+The https://spring.io/[spring.io] site contains several guides that show how to use Spring Data step-by-step:
+
+* https://spring.io/guides/gs/accessing-data-mongodb/[Accessing Data with MongoDB] is a very basic guide that shows you how to create a simple application and how to access data using repositories.
+* https://spring.io/guides/gs/accessing-mongodb-data-rest/[Accessing MongoDB Data with REST] is a guide to creating a REST web service exposing data stored in MongoDB through repositories.
+
+[[examples]]
+== Examples
+
+* https://github.com/spring-projects/spring-data-examples/[Spring Data Examples] contains example projects that explain specific features in more detail.
+
+[[building-from-source]]
 == Building from Source
 
-You don’t need to build from source to use Spring Data (binaries in https://repo.spring.io[repo.spring.io]), but if you want to try out the latest and greatest, Spring Data can be easily built with the https://github.com/takari/maven-wrapper[maven wrapper].
-You also need JDK 1.8.
+You do not need to build from source to use Spring Data. Binaries are available in https://repo.spring.io[repo.spring.io]
+and accessible from Maven using the Maven configuration noted <<maven-configuration,above>>.
+
+NOTE: Configuration for Gradle is similar to Maven.
+
+The best way to get started is by creating a Spring Boot project using MongoDB on https://start.spring.io[start.spring.io].
+Follow this https://start.spring.io/#type=maven-project&language=java&platformVersion=2.5.4&packaging=jar&jvmVersion=1.8&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&dependencies=data-mongodb[link]
+to build an imperative application and this https://start.spring.io/#type=maven-project&language=java&platformVersion=2.5.4&packaging=jar&jvmVersion=1.8&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&dependencies=data-mongodb-reactive[link]
+to build a reactive one.
+
+However, if you want to try out the latest and greatest, Spring Data MongoDB can be easily built with the https://github.com/takari/maven-wrapper[Maven wrapper]
+and minimally, JDK 8 (https://www.oracle.com/java/technologies/downloads/[JDK downloads]).
+
+In order to build Spring Data MongoDB, you will need to https://www.mongodb.com/try/download/community[download]
+and https://docs.mongodb.com/manual/installation/[install a MongoDB distribution].
+
+Once you have installed MongoDB, you need to start a MongoDB server. It is convenient to set an environment variable to
+your MongoDB installation directory (e.g. `MONGODB_HOME`).
+
+To run the full test suite, a https://docs.mongodb.com/manual/tutorial/deploy-replica-set/[MongoDB Replica Set]
+is required.
+
+To run the MongoDB server enter the following command from a command-line:
+
+[source,bash]
+----
+$ $MONGODB_HOME/bin/mongod --dbpath $MONGODB_HOME/runtime/data --ipv6 --port 27017 --replSet rs0
+...
+"msg":"Successfully connected to host"
+----
+
+Once the MongoDB server starts up, you should see the message (`msg`), "_Successfully connected to host_".
+
+Notice the `--dbpath` option to the `mongod` command. You can set this to anything you like, but in this case, we set
+the absolute path to a sub-directory (`runtime/data/`) under the MongoDB installation directory (in `$MONGODB_HOME`).
+
+You need to initialize the MongoDB replica set only once on the first time the MongoDB server is started.
+To initialize the replica set, start a mongo client:
+
+[source,bash]
+----
+$ $MONGODB_HOME/bin/mongo
+MongoDB server version: 5.0.0
+...
+----
+
+Then enter the following command:
+
+[source,bash]
+----
+mongo> rs.initiate({ _id: 'rs0', members: [ { _id: 0, host: '127.0.0.1:27017' } ] })
+----
+
+Finally, on UNIX-based system (for example, Linux or Mac OS X) you may need to adjust the `ulimit`.
+In case you need to, you can adjust the `ulimit` with the following command (32768 is just a recommendation):
+
+[source,bash]
+----
+$ ulimit -n 32768
+----
+
+You can use `ulimit -a` again to verify the `ulimit` for "_open files_" was set appropriately.
+
+Now you are ready to build Spring Data MongoDB. Simply enter the following `mvnw` (Maven Wrapper) command:
 
 [source,bash]
 ----
@@ -261,7 +343,8 @@ You also need JDK 1.8.
 
 If you want to build with the regular `mvn` command, you will need https://maven.apache.org/run-maven/index.html[Maven v3.5.0 or above].
 
-_Also see link:CONTRIBUTING.adoc[CONTRIBUTING.adoc] if you wish to submit pull requests, and in particular please sign the https://cla.pivotal.io/sign/spring[Contributor’s Agreement] before your first non-trivial change._
+_Also see link:CONTRIBUTING.adoc[CONTRIBUTING.adoc] if you wish to submit pull requests, and in particular, please sign
+the https://cla.pivotal.io/sign/spring[Contributor’s Agreement] before your first non-trivial change._
 
 === Building reference documentation
 
@@ -274,17 +357,7 @@ Building the documentation builds also the project without running tests.
 
 The generated documentation is available from `target/site/reference/html/index.html`.
 
-== Guides
-
-The https://spring.io/[spring.io] site contains several guides that show how to use Spring Data step-by-step:
-
-* https://spring.io/guides/gs/accessing-data-mongodb/[Accessing Data with MongoDB] is a very basic guide that shows you how to create a simple application and how to access data using repositories.
-* https://spring.io/guides/gs/accessing-mongodb-data-rest/[Accessing MongoDB Data with REST] is a guide to creating a REST web service exposing data stored in MongoDB through repositories.
-
-== Examples
-
-* https://github.com/spring-projects/spring-data-examples/[Spring Data Examples] contains example projects that explain specific features in more detail.
-
+[[license]]
 == License
 
 Spring Data MongoDB is Open Source software released under the https://www.apache.org/licenses/LICENSE-2.0.html[Apache 2.0 license].

ci/openjdk17-mongodb-4.4/Dockerfile

@@ -7,6 +7,9 @@ ENV TZ=Etc/UTC
 ENV DEBIAN_FRONTEND=noninteractive
 
 RUN set -eux; \
+	sed -i -e 's/archive.ubuntu.com/mirror.one.com/g' /etc/apt/sources.list; \
+	sed -i -e 's/security.ubuntu.com/mirror.one.com/g' /etc/apt/sources.list; \
+	sed -i -e 's/http/https/g' /etc/apt/sources.list ; \
 	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
 	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 656408E390CFB1F5 ; \
 	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.4 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.4.list; \

ci/openjdk17-mongodb-5.0/Dockerfile

@@ -7,12 +7,17 @@ ENV TZ=Etc/UTC
 ENV DEBIAN_FRONTEND=noninteractive
 
 RUN set -eux; \
-	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
-	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 656408E390CFB1F5 ; \
-	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.4 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.4.list; \
+	sed -i -e 's/archive.ubuntu.com/mirror.one.com/g' /etc/apt/sources.list; \
+	sed -i -e 's/security.ubuntu.com/mirror.one.com/g' /etc/apt/sources.list; \
+	sed -i -e 's/http/https/g' /etc/apt/sources.list ; \
+	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 wget ; \
+	# MongoDB 5.0 release signing key
+	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv B00A0BD1E2C63C11 ; \
+	# Needed when MongoDB creates a 5.0 folder.
+	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/5.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-5.0.list; \
 	echo ${TZ} > /etc/timezone;
 
-RUN apt-get update ; \
+RUN apt-get update; \
 	apt-get install -y mongodb-org=${MONGODB} mongodb-org-server=${MONGODB} mongodb-org-shell=${MONGODB} mongodb-org-mongos=${MONGODB} mongodb-org-tools=${MONGODB} ; \
 	apt-get clean; \
 	rm -rf /var/lib/apt/lists/*;

ci/openjdk8-mongodb-4.0/Dockerfile

@@ -1,18 +0,0 @@
-ARG BASE
-FROM ${BASE}
-# Any ARG statements before FROM are cleared.
-ARG MONGODB
-
-ENV TZ=Etc/UTC
-ENV DEBIAN_FRONTEND=noninteractive
-
-RUN RUN set -eux; \
-	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
-	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 9DA31620334BD75D9DCB49F368818C72E52529D4 ; \
-	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.0.list; \
-	echo ${TZ} > /etc/timezone;
-
-RUN apt-get update ; \
-	apt-get install -y mongodb-org=${MONGODB} mongodb-org-server=${MONGODB} mongodb-org-shell=${MONGODB} mongodb-org-mongos=${MONGODB} mongodb-org-tools=${MONGODB} ; \
-	apt-get clean; \
-	rm -rf /var/lib/apt/lists/*;

ci/openjdk8-mongodb-4.4/Dockerfile

@@ -1,20 +0,0 @@
-ARG BASE
-FROM ${BASE}
-# Any ARG statements before FROM are cleared.
-ARG MONGODB
-
-ENV TZ=Etc/UTC
-ENV DEBIAN_FRONTEND=noninteractive
-
-RUN set -eux; \
-	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
-	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 656408E390CFB1F5 ; \
-	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.4 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.4.list; \
-	echo ${TZ} > /etc/timezone;
-
-RUN apt-get update ; \
-	ln -T /bin/true /usr/bin/systemctl ; \
-	apt-get install -y mongodb-org=${MONGODB} mongodb-org-server=${MONGODB} mongodb-org-shell=${MONGODB} mongodb-org-mongos=${MONGODB} mongodb-org-tools=${MONGODB} ; \
-    rm /usr/bin/systemctl ; \
-	apt-get clean ; \
-	rm -rf /var/lib/apt/lists/* ;

ci/pipeline.properties

@@ -1,17 +1,10 @@
 # Java versions
-java.main.tag=8u322-b06-jdk
-java.11.tag=11.0.14.1_1-jdk
-java.15.tag=15.0.2_7-jdk-hotspot
-java.lts.tag=17.0.2_8-jdk
+java.main.tag=17.0.2_8-jdk
 
 # Docker container images - standard
 docker.java.main.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.main.tag}
-docker.java.11.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.11.tag}
-docker.java.15.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/adoptopenjdk:${java.15.tag}
-docker.java.lts.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.lts.tag}
 
 # Supported versions of MongoDB
-docker.mongodb.4.0.version=4.0.28
 docker.mongodb.4.4.version=4.4.12
 docker.mongodb.5.0.version=5.0.6
 

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>3.2.10</version>
+	<version>4.0.0-M2</version>
 	<packaging>pom</packaging>
 
 	<name>Spring Data MongoDB</name>
@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.springframework.data.build</groupId>
 		<artifactId>spring-data-parent</artifactId>
-		<version>2.5.10</version>
+		<version>3.0.0-M2</version>
 	</parent>
 
 	<modules>
@@ -24,10 +24,11 @@
 	</modules>
 
 	<properties>
+		<source.level>16</source.level>
 		<project.type>multi</project.type>
 		<dist.id>spring-data-mongodb</dist.id>
-		<springdata.commons>2.5.10</springdata.commons>
-		<mongo>4.2.3</mongo>
+		<springdata.commons>3.0.0-M2</springdata.commons>
+		<mongo>4.5.0</mongo>
 		<mongo.reactivestreams>${mongo}</mongo.reactivestreams>
 		<jmh.version>1.19</jmh.version>
 	</properties>
@@ -134,18 +135,18 @@
 
 	<repositories>
 		<repository>
-			<id>spring-libs-release</id>
-			<url>https://repo.spring.io/libs-release</url>
+			<id>spring-libs-milestone</id>
+			<url>https://repo.spring.io/libs-milestone</url>
 		</repository>
 		<repository>
 			<id>sonatype-libs-snapshot</id>
 			<url>https://oss.sonatype.org/content/repositories/snapshots</url>
 			<releases>
-        <enabled>false</enabled>
-      </releases>
+				<enabled>false</enabled>
+			</releases>
 			<snapshots>
-        <enabled>true</enabled>
-      </snapshots>
+				<enabled>true</enabled>
+			</snapshots>
 		</repository>
 	</repositories>
 

spring-data-mongodb-benchmarks/pom.xml

@@ -7,7 +7,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.2.10</version>
+		<version>4.0.0-M2</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb-distribution/pom.xml

@@ -14,7 +14,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.2.10</version>
+		<version>4.0.0-M2</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb/pom.xml

@@ -11,7 +11,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.2.10</version>
+		<version>4.0.0-M2</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
@@ -87,6 +87,13 @@
 			<optional>true</optional>
 		</dependency>
 
+		<dependency>
+			<groupId>com.google.code.findbugs</groupId>
+			<artifactId>jsr305</artifactId>
+			<version>3.0.2</version>
+			<optional>true</optional>
+		</dependency>
+
 		<!-- reactive -->
 
 		<dependency>
@@ -115,27 +122,6 @@
 			<optional>true</optional>
 		</dependency>
 
-		<dependency>
-			<groupId>io.reactivex</groupId>
-			<artifactId>rxjava</artifactId>
-			<version>${rxjava}</version>
-			<optional>true</optional>
-		</dependency>
-
-		<dependency>
-			<groupId>io.reactivex</groupId>
-			<artifactId>rxjava-reactive-streams</artifactId>
-			<version>${rxjava-reactive-streams}</version>
-			<optional>true</optional>
-		</dependency>
-
-		<dependency>
-			<groupId>io.reactivex.rxjava2</groupId>
-			<artifactId>rxjava</artifactId>
-			<version>${rxjava2}</version>
-			<optional>true</optional>
-		</dependency>
-
 		<dependency>
 			<groupId>io.reactivex.rxjava3</groupId>
 			<artifactId>rxjava</artifactId>
@@ -145,12 +131,6 @@
 
 		<!-- CDI -->
 		<!-- Dependency order required to build against CDI 1.0 and test with CDI 2.0 -->
-		<dependency>
-			<groupId>org.apache.geronimo.specs</groupId>
-			<artifactId>geronimo-jcdi_2.0_spec</artifactId>
-			<version>1.0.1</version>
-			<scope>test</scope>
-		</dependency>
 
 		<dependency>
 			<groupId>javax.interceptor</groupId>
@@ -160,31 +140,48 @@
 		</dependency>
 
 		<dependency>
-			<groupId>javax.enterprise</groupId>
-			<artifactId>cdi-api</artifactId>
+			<groupId>jakarta.enterprise</groupId>
+			<artifactId>jakarta.enterprise.cdi-api</artifactId>
 			<version>${cdi}</version>
 			<scope>provided</scope>
 			<optional>true</optional>
 		</dependency>
 
 		<dependency>
-			<groupId>javax.annotation</groupId>
-			<artifactId>javax.annotation-api</artifactId>
-			<version>${javax-annotation-api}</version>
+			<groupId>jakarta.annotation</groupId>
+			<artifactId>jakarta.annotation-api</artifactId>
+			<version>${jakarta-annotation-api}</version>
 			<scope>test</scope>
 		</dependency>
 
 		<dependency>
 			<groupId>org.apache.openwebbeans</groupId>
 			<artifactId>openwebbeans-se</artifactId>
+			<classifier>jakarta</classifier>
+			<version>${webbeans}</version>
+			<scope>test</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.openwebbeans</groupId>
+			<artifactId>openwebbeans-spi</artifactId>
+			<classifier>jakarta</classifier>
+			<version>${webbeans}</version>
+			<scope>test</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.openwebbeans</groupId>
+			<artifactId>openwebbeans-impl</artifactId>
+			<classifier>jakarta</classifier>
 			<version>${webbeans}</version>
 			<scope>test</scope>
 		</dependency>
 
 		<!-- JSR 303 Validation -->
 		<dependency>
-			<groupId>javax.validation</groupId>
-			<artifactId>validation-api</artifactId>
+			<groupId>jakarta.validation</groupId>
+			<artifactId>jakarta.validation-api</artifactId>
 			<version>${validation}</version>
 			<optional>true</optional>
 		</dependency>
@@ -199,28 +196,23 @@
 		<dependency>
 			<groupId>org.hibernate</groupId>
 			<artifactId>hibernate-validator</artifactId>
-			<version>5.4.3.Final</version>
+			<version>7.0.1.Final</version>
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>jakarta.el</groupId>
+			<artifactId>jakarta.el-api</artifactId>
+			<version>4.0.0</version>
+			<scope>provided</scope>
+			<optional>true</optional>
+		</dependency>
+
 		<dependency>
 			<groupId>org.glassfish</groupId>
-			<artifactId>javax.el</artifactId>
-			<version>3.0.1-b11</version>
-			<scope>test</scope>
-		</dependency>
-
-		<dependency>
-			<groupId>joda-time</groupId>
-			<artifactId>joda-time</artifactId>
-			<version>${jodatime}</version>
-			<scope>test</scope>
-		</dependency>
-
-		<dependency>
-			<groupId>org.threeten</groupId>
-			<artifactId>threetenbp</artifactId>
-			<version>${threetenbp}</version>
+			<artifactId>jakarta.el</artifactId>
+			<version>4.0.2</version>
+			<scope>provided</scope>
 			<optional>true</optional>
 		</dependency>
 
@@ -230,13 +222,6 @@
 			<optional>true</optional>
 		</dependency>
 
-		<dependency>
-			<groupId>org.slf4j</groupId>
-			<artifactId>jul-to-slf4j</artifactId>
-			<version>${slf4j}</version>
-			<scope>test</scope>
-		</dependency>
-
 		<dependency>
 			<groupId>nl.jqno.equalsverifier</groupId>
 			<artifactId>equalsverifier</artifactId>
@@ -272,9 +257,9 @@
 		</dependency>
 
 		<dependency>
-			<groupId>javax.transaction</groupId>
-			<artifactId>jta</artifactId>
-			<version>1.1</version>
+			<groupId>jakarta.transaction</groupId>
+			<artifactId>jakarta.transaction-api</artifactId>
+			<version>2.0.0</version>
 			<scope>test</scope>
 		</dependency>
 
@@ -310,6 +295,15 @@
 			<scope>test</scope>
 		</dependency>
 
+		<!-- jMolecules -->
+
+		<dependency>
+			<groupId>org.jmolecules</groupId>
+			<artifactId>jmolecules-ddd</artifactId>
+			<version>${jmolecules}</version>
+			<scope>test</scope>
+		</dependency>
+
 	</dependencies>
 
 	<build>

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/BindableMongoExpression.java

@@ -103,19 +103,11 @@ public class BindableMongoExpression implements MongoExpression {
 		return new BindableMongoExpression(expressionString, codecRegistryProvider, args);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoExpression#toDocument()
-	 */
 	@Override
 	public Document toDocument() {
 		return target.get();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.lang.Object#toString()
-	 */
 	@Override
 	public String toString() {
 		return "BindableMongoExpression{" + "expressionString='" + expressionString + '\'' + ", args="

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoDatabaseUtils.java

@@ -193,19 +193,11 @@ public class MongoDatabaseUtils {
 			this.resourceHolder = resourceHolder;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.ResourceHolderSynchronization#shouldReleaseBeforeCompletion()
-		 */
 		@Override
 		protected boolean shouldReleaseBeforeCompletion() {
 			return false;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.ResourceHolderSynchronization#processResourceAfterCommit(java.lang.Object)
-		 */
 		@Override
 		protected void processResourceAfterCommit(MongoResourceHolder resourceHolder) {
 
@@ -214,10 +206,6 @@ public class MongoDatabaseUtils {
 			}
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.ResourceHolderSynchronization#afterCompletion(int)
-		 */
 		@Override
 		public void afterCompletion(int status) {
 
@@ -228,10 +216,6 @@ public class MongoDatabaseUtils {
 			super.afterCompletion(status);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.ResourceHolderSynchronization#releaseResource(java.lang.Object, java.lang.Object)
-		 */
 		@Override
 		protected void releaseResource(MongoResourceHolder resourceHolder, Object resourceKey) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoDbFactory.java

@@ -1,57 +0,0 @@
-/*
- * Copyright 2011-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.data.mongodb;
-
-import org.springframework.dao.DataAccessException;
-
-import com.mongodb.client.MongoDatabase;
-
-/**
- * Interface for factories creating {@link MongoDatabase} instances.
- *
- * @author Mark Pollack
- * @author Thomas Darimont
- * @author Christoph Strobl
- * @deprecated since 3.0, use {@link MongoDatabaseFactory} instead.
- */
-@Deprecated
-public interface MongoDbFactory extends MongoDatabaseFactory {
-
-	/**
-	 * Creates a default {@link MongoDatabase} instance.
-	 *
-	 * @return never {@literal null}.
-	 * @throws DataAccessException
-	 * @deprecated since 3.0. Use {@link #getMongoDatabase()} instead.
-	 */
-	@Deprecated
-	default MongoDatabase getDb() throws DataAccessException {
-		return getMongoDatabase();
-	}
-
-	/**
-	 * Obtain a {@link MongoDatabase} instance to access the database with the given name.
-	 *
-	 * @param dbName must not be {@literal null} or empty.
-	 * @return never {@literal null}.
-	 * @throws DataAccessException
-	 * @deprecated since 3.0. Use {@link #getMongoDatabase(String)} instead.
-	 */
-	@Deprecated
-	default MongoDatabase getDb(String dbName) throws DataAccessException {
-		return getMongoDatabase(dbName);
-	}
-}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoTransactionManager.java

@@ -106,10 +106,6 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		this.options = options;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doGetTransaction()
-	 */
 	@Override
 	protected Object doGetTransaction() throws TransactionException {
 
@@ -118,19 +114,11 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		return new MongoTransactionObject(resourceHolder);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#isExistingTransaction(java.lang.Object)
-	 */
 	@Override
 	protected boolean isExistingTransaction(Object transaction) throws TransactionException {
 		return extractMongoTransaction(transaction).hasResourceHolder();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doBegin(java.lang.Object, org.springframework.transaction.TransactionDefinition)
-	 */
 	@Override
 	protected void doBegin(Object transaction, TransactionDefinition definition) throws TransactionException {
 
@@ -160,10 +148,6 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		TransactionSynchronizationManager.bindResource(getRequiredDbFactory(), resourceHolder);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doSuspend(java.lang.Object)
-	 */
 	@Override
 	protected Object doSuspend(Object transaction) throws TransactionException {
 
@@ -173,19 +157,11 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		return TransactionSynchronizationManager.unbindResource(getRequiredDbFactory());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doResume(java.lang.Object, java.lang.Object)
-	 */
 	@Override
 	protected void doResume(@Nullable Object transaction, Object suspendedResources) {
 		TransactionSynchronizationManager.bindResource(getRequiredDbFactory(), suspendedResources);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doCommit(org.springframework.transaction.support.DefaultTransactionStatus)
-	 */
 	@Override
 	protected final void doCommit(DefaultTransactionStatus status) throws TransactionException {
 
@@ -236,10 +212,6 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		transactionObject.commitTransaction();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doRollback(org.springframework.transaction.support.DefaultTransactionStatus)
-	 */
 	@Override
 	protected void doRollback(DefaultTransactionStatus status) throws TransactionException {
 
@@ -259,10 +231,6 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		}
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doSetRollbackOnly(org.springframework.transaction.support.DefaultTransactionStatus)
-	 */
 	@Override
 	protected void doSetRollbackOnly(DefaultTransactionStatus status) throws TransactionException {
 
@@ -270,10 +238,6 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		transactionObject.getRequiredResourceHolder().setRollbackOnly();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doCleanupAfterCompletion(java.lang.Object)
-	 */
 	@Override
 	protected void doCleanupAfterCompletion(Object transaction) {
 
@@ -325,19 +289,11 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		return dbFactory;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.support.ResourceTransactionManager#getResourceFactory()
-	 */
 	@Override
 	public MongoDatabaseFactory getResourceFactory() {
 		return getRequiredDbFactory();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
-	 */
 	@Override
 	public void afterPropertiesSet() {
 		getRequiredDbFactory();
@@ -505,19 +461,11 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 			return session;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see  org.springframework.transaction.support.SmartTransactionObject#isRollbackOnly()
-		 */
 		@Override
 		public boolean isRollbackOnly() {
 			return this.resourceHolder != null && this.resourceHolder.isRollbackOnly();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see  org.springframework.transaction.support.SmartTransactionObject#flush()
-		 */
 		@Override
 		public void flush() {
 			TransactionSynchronizationUtils.triggerFlush();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/ReactiveMongoDatabaseUtils.java

@@ -214,19 +214,11 @@ public class ReactiveMongoDatabaseUtils {
 			this.resourceHolder = resourceHolder;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.reactive.ReactiveResourceSynchronization#shouldReleaseBeforeCompletion()
-		 */
 		@Override
 		protected boolean shouldReleaseBeforeCompletion() {
 			return false;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.reactive.ReactiveResourceSynchronization#processResourceAfterCommit(java.lang.Object)
-		 */
 		@Override
 		protected Mono<Void> processResourceAfterCommit(ReactiveMongoResourceHolder resourceHolder) {
 
@@ -237,10 +229,6 @@ public class ReactiveMongoDatabaseUtils {
 			return Mono.empty();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.reactive.ReactiveResourceSynchronization#afterCompletion(int)
-		 */
 		@Override
 		public Mono<Void> afterCompletion(int status) {
 
@@ -256,10 +244,6 @@ public class ReactiveMongoDatabaseUtils {
 			});
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.reactive.ReactiveResourceSynchronization#releaseResource(java.lang.Object, java.lang.Object)
-		 */
 		@Override
 		protected Mono<Void> releaseResource(ReactiveMongoResourceHolder resourceHolder, Object resourceKey) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/ReactiveMongoTransactionManager.java

@@ -110,10 +110,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		this.options = options;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doGetTransaction(org.springframework.transaction.reactive.TransactionSynchronizationManager)
-	 */
 	@Override
 	protected Object doGetTransaction(TransactionSynchronizationManager synchronizationManager)
 			throws TransactionException {
@@ -123,19 +119,11 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		return new ReactiveMongoTransactionObject(resourceHolder);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#isExistingTransaction(java.lang.Object)
-	 */
 	@Override
 	protected boolean isExistingTransaction(Object transaction) throws TransactionException {
 		return extractMongoTransaction(transaction).hasResourceHolder();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doBegin(org.springframework.transaction.reactive.TransactionSynchronizationManager, java.lang.Object, org.springframework.transaction.TransactionDefinition)
-	 */
 	@Override
 	protected Mono<Void> doBegin(TransactionSynchronizationManager synchronizationManager, Object transaction,
 			TransactionDefinition definition) throws TransactionException {
@@ -175,10 +163,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doSuspend(org.springframework.transaction.reactive.TransactionSynchronizationManager, java.lang.Object)
-	 */
 	@Override
 	protected Mono<Object> doSuspend(TransactionSynchronizationManager synchronizationManager, Object transaction)
 			throws TransactionException {
@@ -192,10 +176,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doResume(org.springframework.transaction.reactive.TransactionSynchronizationManager, java.lang.Object, java.lang.Object)
-	 */
 	@Override
 	protected Mono<Void> doResume(TransactionSynchronizationManager synchronizationManager, @Nullable Object transaction,
 			Object suspendedResources) {
@@ -203,10 +183,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 				.fromRunnable(() -> synchronizationManager.bindResource(getRequiredDatabaseFactory(), suspendedResources));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doCommit(org.springframework.transaction.reactive.TransactionSynchronizationManager, org.springframework.transaction.reactive.GenericReactiveTransaction)
-	 */
 	@Override
 	protected final Mono<Void> doCommit(TransactionSynchronizationManager synchronizationManager,
 			GenericReactiveTransaction status) throws TransactionException {
@@ -243,10 +219,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		return transactionObject.commitTransaction();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doRollback(org.springframework.transaction.reactive.TransactionSynchronizationManager, org.springframework.transaction.reactive.GenericReactiveTransaction)
-	 */
 	@Override
 	protected Mono<Void> doRollback(TransactionSynchronizationManager synchronizationManager,
 			GenericReactiveTransaction status) {
@@ -268,10 +240,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doSetRollbackOnly(org.springframework.transaction.reactive.TransactionSynchronizationManager, org.springframework.transaction.reactive.GenericReactiveTransaction)
-	 */
 	@Override
 	protected Mono<Void> doSetRollbackOnly(TransactionSynchronizationManager synchronizationManager,
 			GenericReactiveTransaction status) throws TransactionException {
@@ -282,10 +250,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.transaction.reactive.AbstractReactiveTransactionManager#doCleanupAfterCompletion(org.springframework.transaction.reactive.TransactionSynchronizationManager, java.lang.Object)
-	 */
 	@Override
 	protected Mono<Void> doCleanupAfterCompletion(TransactionSynchronizationManager synchronizationManager,
 			Object transaction) {
@@ -340,10 +304,6 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		return databaseFactory;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
-	 */
 	@Override
 	public void afterPropertiesSet() {
 		getRequiredDatabaseFactory();
@@ -509,19 +469,11 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 			return session;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.SmartTransactionObject#isRollbackOnly()
-		 */
 		@Override
 		public boolean isRollbackOnly() {
 			return this.resourceHolder != null && this.resourceHolder.isRollbackOnly();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.transaction.support.SmartTransactionObject#flush()
-		 */
 		@Override
 		public void flush() {
 			throw new UnsupportedOperationException("flush() not supported");

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/SessionAwareMethodInterceptor.java

@@ -95,10 +95,6 @@ public class SessionAwareMethodInterceptor<D, C> implements MethodInterceptor {
 		this.sessionType = sessionType;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.aopalliance.intercept.MethodInterceptor(org.aopalliance.intercept.MethodInvocation)
-	 */
 	@Nullable
 	@Override
 	public Object invoke(MethodInvocation methodInvocation) throws Throwable {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/SpringDataMongoDB.java

@@ -15,8 +15,8 @@
  */
 package org.springframework.data.mongodb;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.data.util.Version;
 import org.springframework.util.StringUtils;
 
@@ -31,7 +31,7 @@ import com.mongodb.MongoDriverInformation;
  */
 public class SpringDataMongoDB {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(SpringDataMongoDB.class);
+	private static final Log LOGGER = LogFactory.getLog(SpringDataMongoDB.class);
 
 	private static final Version FALLBACK_VERSION = new Version(3);
 	private static final MongoDriverInformation DRIVER_INFORMATION = MongoDriverInformation
@@ -68,7 +68,7 @@ public class SpringDataMongoDB {
 		try {
 			return Version.parse(versionString);
 		} catch (Exception e) {
-			LOGGER.debug("Cannot read Spring Data MongoDB version '{}'.", versionString);
+			LOGGER.debug(String.format("Cannot read Spring Data MongoDB version '%s'.", versionString));
 		}
 
 		return FALLBACK_VERSION;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoClientConfiguration.java

@@ -25,9 +25,7 @@ import org.springframework.data.mongodb.core.convert.DbRefResolver;
 import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
-import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
-import org.springframework.lang.Nullable;
 
 import com.mongodb.MongoClientSettings;
 import com.mongodb.MongoClientSettings.Builder;
@@ -80,24 +78,6 @@ public abstract class AbstractMongoClientConfiguration extends MongoConfiguratio
 		return new SimpleMongoClientDatabaseFactory(mongoClient(), getDatabaseName());
 	}
 
-	/**
-	 * Return the base package to scan for mapped {@link Document}s. Will return the package name of the configuration
-	 * class' (the concrete class, not this one here) by default. So if you have a {@code com.acme.AppConfig} extending
-	 * {@link AbstractMongoClientConfiguration} the base package will be considered {@code com.acme} unless the method is
-	 * overridden to implement alternate behavior.
-	 *
-	 * @return the base package to scan for mapped {@link Document} classes or {@literal null} to not enable scanning for
-	 *         entities.
-	 * @deprecated use {@link #getMappingBasePackages()} instead.
-	 */
-	@Deprecated
-	@Nullable
-	protected String getMappingBasePackage() {
-
-		Package mappingBasePackage = getClass().getPackage();
-		return mappingBasePackage == null ? null : mappingBasePackage.getName();
-	}
-
 	/**
 	 * Creates a {@link MappingMongoConverter} using the configured {@link #mongoDbFactory()} and
 	 * {@link #mongoMappingContext(MongoCustomConversions)}. Will get {@link #customConversions()} applied.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ConnectionStringPropertyEditor.java

@@ -30,10 +30,6 @@ import com.mongodb.ConnectionString;
  */
 public class ConnectionStringPropertyEditor extends PropertyEditorSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
-	 */
 	@Override
 	public void setAsText(@Nullable String connectionString) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/GridFsTemplateParser.java

@@ -34,10 +34,6 @@ import org.w3c.dom.Element;
  */
 class GridFsTemplateParser extends AbstractBeanDefinitionParser {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#resolveId(org.w3c.dom.Element, org.springframework.beans.factory.support.AbstractBeanDefinition, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
 			throws BeanDefinitionStoreException {
@@ -46,10 +42,6 @@ class GridFsTemplateParser extends AbstractBeanDefinitionParser {
 		return StringUtils.hasText(id) ? id : BeanNames.GRID_FS_TEMPLATE_BEAN_NAME;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#parseInternal(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java

@@ -80,7 +80,7 @@ import org.w3c.dom.Element;
 public class MappingMongoConverterParser implements BeanDefinitionParser {
 
 	private static final String BASE_PACKAGE = "base-package";
-	private static final boolean JSR_303_PRESENT = ClassUtils.isPresent("javax.validation.Validator",
+	private static final boolean JSR_303_PRESENT = ClassUtils.isPresent("jakarta.validation.Validator",
 			MappingMongoConverterParser.class.getClassLoader());
 
 	/* (non-Javadoc)
@@ -376,10 +376,6 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 			this.delegates = new HashSet<>(Arrays.asList(filters));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.core.type.filter.TypeFilter#match(org.springframework.core.type.classreading.MetadataReader, org.springframework.core.type.classreading.MetadataReaderFactory)
-		 */
 		public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory)
 				throws IOException {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoAuditingBeanDefinitionParser.java

@@ -47,28 +47,16 @@ public class MongoAuditingBeanDefinitionParser extends AbstractSingleBeanDefinit
 	private static boolean PROJECT_REACTOR_AVAILABLE = ClassUtils.isPresent("reactor.core.publisher.Mono",
 			MongoAuditingRegistrar.class.getClassLoader());
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser#getBeanClass(org.w3c.dom.Element)
-	 */
 	@Override
 	protected Class<?> getBeanClass(Element element) {
 		return AuditingEntityCallback.class;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#shouldGenerateId()
-	 */
 	@Override
 	protected boolean shouldGenerateId() {
 		return true;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser#doParse(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext, org.springframework.beans.factory.support.BeanDefinitionBuilder)
-	 */
 	@Override
 	protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoAuditingRegistrar.java

@@ -18,6 +18,7 @@ package org.springframework.data.mongodb.config;
 import java.lang.annotation.Annotation;
 
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
@@ -27,6 +28,8 @@ import org.springframework.data.auditing.IsNewAwareAuditingHandler;
 import org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport;
 import org.springframework.data.auditing.config.AuditingConfiguration;
 import org.springframework.data.config.ParsingUtils;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.mapping.event.AuditingEntityCallback;
 import org.springframework.util.Assert;
 
@@ -39,28 +42,16 @@ import org.springframework.util.Assert;
  */
 class MongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAnnotation()
-	 */
 	@Override
 	protected Class<? extends Annotation> getAnnotation() {
 		return EnableMongoAuditing.class;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAuditingHandlerBeanName()
-	 */
 	@Override
 	protected String getAuditingHandlerBeanName() {
 		return "mongoAuditingHandler";
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#registerBeanDefinitions(org.springframework.core.type.AnnotationMetadata, org.springframework.beans.factory.support.BeanDefinitionRegistry)
-	 */
 	@Override
 	public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry registry) {
 
@@ -70,10 +61,6 @@ class MongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 		super.registerBeanDefinitions(annotationMetadata, registry);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAuditHandlerBeanDefinitionBuilder(org.springframework.data.auditing.config.AuditingConfiguration)
-	 */
 	@Override
 	protected BeanDefinitionBuilder getAuditHandlerBeanDefinitionBuilder(AuditingConfiguration configuration) {
 
@@ -81,17 +68,13 @@ class MongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 
 		BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(IsNewAwareAuditingHandler.class);
 
-		BeanDefinitionBuilder definition = BeanDefinitionBuilder.genericBeanDefinition(PersistentEntitiesFactoryBean.class);
-		definition.setAutowireMode(AbstractBeanDefinition.AUTOWIRE_CONSTRUCTOR);
+		BeanDefinitionBuilder definition = BeanDefinitionBuilder.genericBeanDefinition(org.springframework.data.repository.config.PersistentEntitiesFactoryBean.class);
+		definition.addConstructorArgValue(new RuntimeBeanReference(MappingContext.class));
 
 		builder.addConstructorArgValue(definition.getBeanDefinition());
 		return configureDefaultAuditHandlerAttributes(configuration, builder);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#registerAuditListener(org.springframework.beans.factory.config.BeanDefinition, org.springframework.beans.factory.support.BeanDefinitionRegistry)
-	 */
 	@Override
 	protected void registerAuditListenerBeanDefinition(BeanDefinition auditingHandlerDefinition,
 			BeanDefinitionRegistry registry) {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoClientParser.java

@@ -35,10 +35,6 @@ import org.w3c.dom.Element;
  */
 public class MongoClientParser implements BeanDefinitionParser {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.BeanDefinitionParser#parse(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 
 		Object source = parserContext.extractSource(element);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoCredentialPropertyEditor.java

@@ -51,10 +51,6 @@ public class MongoCredentialPropertyEditor extends PropertyEditorSupport {
 	private static final String OPTIONS_DELIMITER = "?";
 	private static final String OPTION_VALUE_DELIMITER = "&";
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
-	 */
 	@Override
 	public void setAsText(@Nullable String text) throws IllegalArgumentException {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoDbFactoryParser.java

@@ -62,10 +62,6 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 		MONGO_URI_ALLOWED_ADDITIONAL_ATTRIBUTES = Collections.unmodifiableSet(mongoUriAllowedAdditionalAttributes);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#resolveId(org.w3c.dom.Element, org.springframework.beans.factory.support.AbstractBeanDefinition, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
 			throws BeanDefinitionStoreException {
@@ -74,10 +70,6 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 		return StringUtils.hasText(id) ? id : BeanNames.DB_FACTORY_BEAN_NAME;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#parseInternal(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoNamespaceHandler.java

@@ -26,10 +26,6 @@ import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
  */
 public class MongoNamespaceHandler extends NamespaceHandlerSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.NamespaceHandler#init()
-	 */
 	public void init() {
 
 		registerBeanDefinitionParser("mapping-converter", new MappingMongoConverterParser());

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoParsingUtils.java

@@ -22,9 +22,12 @@ import java.util.Map;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.CustomEditorConfigurer;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.BeanDefinitionValidationException;
 import org.springframework.beans.factory.support.ManagedMap;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.data.mongodb.core.MongoClientSettingsFactoryBean;
+import org.springframework.data.mongodb.core.MongoServerApiFactoryBean;
+import org.springframework.util.StringUtils;
 import org.springframework.util.xml.DomUtils;
 import org.w3c.dom.Element;
 
@@ -37,7 +40,6 @@ import org.w3c.dom.Element;
  * @author Christoph Strobl
  * @author Mark Paluch
  */
-@SuppressWarnings("deprecation")
 abstract class MongoParsingUtils {
 
 	private MongoParsingUtils() {}
@@ -112,6 +114,20 @@ abstract class MongoParsingUtils {
 		// Field level encryption
 		setPropertyReference(clientOptionsDefBuilder, settingsElement, "encryption-settings-ref", "autoEncryptionSettings");
 
+		// ServerAPI
+		if (StringUtils.hasText(settingsElement.getAttribute("server-api-version"))) {
+
+			MongoServerApiFactoryBean serverApiFactoryBean = new MongoServerApiFactoryBean();
+			serverApiFactoryBean.setVersion(settingsElement.getAttribute("server-api-version"));
+			try {
+				clientOptionsDefBuilder.addPropertyValue("serverApi", serverApiFactoryBean.getObject());
+			} catch (Exception exception) {
+				throw new BeanDefinitionValidationException("Non parsable server-api.", exception);
+			}
+		} else {
+			setPropertyReference(clientOptionsDefBuilder, settingsElement, "server-api-ref", "serverApi");
+		}
+
 		// and the rest
 
 		mongoClientBuilder.addPropertyValue("mongoClientSettings", clientOptionsDefBuilder.getBeanDefinition());

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoTemplateParser.java

@@ -39,10 +39,6 @@ import org.w3c.dom.Element;
  */
 class MongoTemplateParser extends AbstractBeanDefinitionParser {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#resolveId(org.w3c.dom.Element, org.springframework.beans.factory.support.AbstractBeanDefinition, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
 			throws BeanDefinitionStoreException {
@@ -51,10 +47,6 @@ class MongoTemplateParser extends AbstractBeanDefinitionParser {
 		return StringUtils.hasText(id) ? id : BeanNames.MONGO_TEMPLATE_BEAN_NAME;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#parseInternal(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/PersistentEntitiesFactoryBean.java

@@ -41,19 +41,11 @@ public class PersistentEntitiesFactoryBean implements FactoryBean<PersistentEnti
 		this.converter = converter;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.FactoryBean#getObject()
-	 */
 	@Override
 	public PersistentEntities getObject() {
 		return PersistentEntities.of(converter.getMappingContext());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.FactoryBean#getObjectType()
-	 */
 	@Override
 	public Class<?> getObjectType() {
 		return PersistentEntities.class;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ReactiveMongoAuditingRegistrar.java

@@ -38,28 +38,16 @@ import org.springframework.util.Assert;
  */
 class ReactiveMongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAnnotation()
-	 */
 	@Override
 	protected Class<? extends Annotation> getAnnotation() {
 		return EnableReactiveMongoAuditing.class;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAuditingHandlerBeanName()
-	 */
 	@Override
 	protected String getAuditingHandlerBeanName() {
 		return "reactiveMongoAuditingHandler";
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAuditHandlerBeanDefinitionBuilder(org.springframework.data.auditing.config.AuditingConfiguration)
-	 */
 	@Override
 	protected BeanDefinitionBuilder getAuditHandlerBeanDefinitionBuilder(AuditingConfiguration configuration) {
 
@@ -74,10 +62,6 @@ class ReactiveMongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupp
 		return configureDefaultAuditHandlerAttributes(configuration, builder);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#registerAuditListener(org.springframework.beans.factory.config.BeanDefinition, org.springframework.beans.factory.support.BeanDefinitionRegistry)
-	 */
 	@Override
 	protected void registerAuditListenerBeanDefinition(BeanDefinition auditingHandlerDefinition,
 			BeanDefinitionRegistry registry) {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ReadConcernPropertyEditor.java

@@ -32,10 +32,6 @@ import com.mongodb.ReadConcernLevel;
  */
 public class ReadConcernPropertyEditor extends PropertyEditorSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.xml.BeanDefinitionParser#parse(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
-	 */
 	@Override
 	public void setAsText(@Nullable String readConcernString) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ReadPreferencePropertyEditor.java

@@ -29,10 +29,6 @@ import com.mongodb.ReadPreference;
  */
 public class ReadPreferencePropertyEditor extends PropertyEditorSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
-	 */
 	@Override
 	public void setAsText(@Nullable String readPreferenceString) throws IllegalArgumentException {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ServerAddressPropertyEditor.java

@@ -21,8 +21,8 @@ import java.net.UnknownHostException;
 import java.util.HashSet;
 import java.util.Set;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -43,13 +43,9 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 	 * A port is a number without a leading 0 at the end of the address that is proceeded by just a single :.
 	 */
 	private static final String HOST_PORT_SPLIT_PATTERN = "(?<!:):(?=[123456789]\\d*$)";
-	private static final String COULD_NOT_PARSE_ADDRESS_MESSAGE = "Could not parse address {} '{}'. Check your replica set configuration!";
-	private static final Logger LOG = LoggerFactory.getLogger(ServerAddressPropertyEditor.class);
+	private static final String COULD_NOT_PARSE_ADDRESS_MESSAGE = "Could not parse address %s '%s'. Check your replica set configuration!";
+	private static final Log LOG = LogFactory.getLog(ServerAddressPropertyEditor.class);
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
-	 */
 	@Override
 	public void setAsText(@Nullable String replicaSetString) {
 
@@ -88,14 +84,18 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 	private ServerAddress parseServerAddress(String source) {
 
 		if (!StringUtils.hasText(source)) {
-			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
+			if(LOG.isWarnEnabled()) {
+				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source));
+			}
 			return null;
 		}
 
 		String[] hostAndPort = extractHostAddressAndPort(source.trim());
 
 		if (hostAndPort.length > 2) {
-			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
+			if(LOG.isWarnEnabled()) {
+				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source));
+			}
 			return null;
 		}
 
@@ -105,9 +105,13 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 
 			return port == null ? new ServerAddress(hostAddress) : new ServerAddress(hostAddress, port);
 		} catch (UnknownHostException e) {
-			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "host", hostAndPort[0]);
+			if(LOG.isWarnEnabled()) {
+				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "host", hostAndPort[0]));
+			}
 		} catch (NumberFormatException e) {
-			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "port", hostAndPort[1]);
+			if(LOG.isWarnEnabled()) {
+				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "port", hostAndPort[1]));
+			}
 		}
 
 		return null;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/StringToWriteConcernConverter.java

@@ -26,10 +26,6 @@ import com.mongodb.WriteConcern;
  */
 public class StringToWriteConcernConverter implements Converter<String, WriteConcern> {
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
-	 */
 	public WriteConcern convert(String source) {
 
 		WriteConcern writeConcern = WriteConcern.valueOf(source);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/UUidRepresentationPropertyEditor.java

@@ -29,10 +29,6 @@ import org.springframework.util.StringUtils;
  */
 public class UUidRepresentationPropertyEditor extends PropertyEditorSupport {
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
-	 */
 	@Override
 	public void setAsText(@Nullable String value) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ChangeStreamEvent.java

@@ -189,10 +189,6 @@ public class ChangeStreamEvent<T> {
 				String.format("No converter found capable of converting %s to %s", fullDocument.getClass(), targetType));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.lang.Object#toString()
-	 */
 	@Override
 	public String toString() {
 		return "ChangeStreamEvent {" + "raw=" + raw + ", targetType=" + targetType + '}';

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/CollectionOptions.java

@@ -17,8 +17,11 @@ package org.springframework.data.mongodb.core;
 
 import java.util.Optional;
 
+import org.springframework.data.mongodb.core.mapping.Field;
 import org.springframework.data.mongodb.core.query.Collation;
 import org.springframework.data.mongodb.core.schema.MongoJsonSchema;
+import org.springframework.data.mongodb.core.timeseries.Granularity;
+import org.springframework.data.mongodb.core.timeseries.GranularityDefinition;
 import org.springframework.data.mongodb.core.validation.Validator;
 import org.springframework.data.util.Optionals;
 import org.springframework.lang.Nullable;
@@ -42,29 +45,18 @@ public class CollectionOptions {
 	private @Nullable Boolean capped;
 	private @Nullable Collation collation;
 	private ValidationOptions validationOptions;
-
-	/**
-	 * Constructs a new <code>CollectionOptions</code> instance.
-	 *
-	 * @param size the collection size in bytes, this data space is preallocated. Can be {@literal null}.
-	 * @param maxDocuments the maximum number of documents in the collection. Can be {@literal null}.
-	 * @param capped true to created a "capped" collection (fixed size with auto-FIFO behavior based on insertion order),
-	 *          false otherwise. Can be {@literal null}.
-	 * @deprecated since 2.0 please use {@link CollectionOptions#empty()} as entry point.
-	 */
-	@Deprecated
-	public CollectionOptions(@Nullable Long size, @Nullable Long maxDocuments, @Nullable Boolean capped) {
-		this(size, maxDocuments, capped, null, ValidationOptions.none());
-	}
+	private @Nullable TimeSeriesOptions timeSeriesOptions;
 
 	private CollectionOptions(@Nullable Long size, @Nullable Long maxDocuments, @Nullable Boolean capped,
-			@Nullable Collation collation, ValidationOptions validationOptions) {
+			@Nullable Collation collation, ValidationOptions validationOptions,
+			@Nullable TimeSeriesOptions timeSeriesOptions) {
 
 		this.maxDocuments = maxDocuments;
 		this.size = size;
 		this.capped = capped;
 		this.collation = collation;
 		this.validationOptions = validationOptions;
+		this.timeSeriesOptions = timeSeriesOptions;
 	}
 
 	/**
@@ -78,7 +70,7 @@ public class CollectionOptions {
 
 		Assert.notNull(collation, "Collation must not be null!");
 
-		return new CollectionOptions(null, null, null, collation, ValidationOptions.none());
+		return new CollectionOptions(null, null, null, collation, ValidationOptions.none(), null);
 	}
 
 	/**
@@ -88,7 +80,21 @@ public class CollectionOptions {
 	 * @since 2.0
 	 */
 	public static CollectionOptions empty() {
-		return new CollectionOptions(null, null, null, null, ValidationOptions.none());
+		return new CollectionOptions(null, null, null, null, ValidationOptions.none(), null);
+	}
+
+	/**
+	 * Quick way to set up {@link CollectionOptions} for a Time Series collection. For more advanced settings use
+	 * {@link #timeSeries(TimeSeriesOptions)}.
+	 *
+	 * @param timeField The name of the property which contains the date in each time series document. Must not be
+	 *          {@literal null}.
+	 * @return new instance of {@link CollectionOptions}.
+	 * @see #timeSeries(TimeSeriesOptions)
+	 * @since 3.3
+	 */
+	public static CollectionOptions timeSeries(String timeField) {
+		return empty().timeSeries(TimeSeriesOptions.timeSeries(timeField));
 	}
 
 	/**
@@ -99,7 +105,7 @@ public class CollectionOptions {
 	 * @since 2.0
 	 */
 	public CollectionOptions capped() {
-		return new CollectionOptions(size, maxDocuments, true, collation, validationOptions);
+		return new CollectionOptions(size, maxDocuments, true, collation, validationOptions, null);
 	}
 
 	/**
@@ -110,7 +116,7 @@ public class CollectionOptions {
 	 * @since 2.0
 	 */
 	public CollectionOptions maxDocuments(long maxDocuments) {
-		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions);
+		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions, timeSeriesOptions);
 	}
 
 	/**
@@ -121,7 +127,7 @@ public class CollectionOptions {
 	 * @since 2.0
 	 */
 	public CollectionOptions size(long size) {
-		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions);
+		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions, timeSeriesOptions);
 	}
 
 	/**
@@ -132,7 +138,7 @@ public class CollectionOptions {
 	 * @since 2.0
 	 */
 	public CollectionOptions collation(@Nullable Collation collation) {
-		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions);
+		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions, timeSeriesOptions);
 	}
 
 	/**
@@ -252,7 +258,20 @@ public class CollectionOptions {
 	public CollectionOptions validation(ValidationOptions validationOptions) {
 
 		Assert.notNull(validationOptions, "ValidationOptions must not be null!");
-		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions);
+		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions, timeSeriesOptions);
+	}
+
+	/**
+	 * Create new {@link CollectionOptions} with the given {@link TimeSeriesOptions}.
+	 *
+	 * @param timeSeriesOptions must not be {@literal null}.
+	 * @return new instance of {@link CollectionOptions}.
+	 * @since 3.3
+	 */
+	public CollectionOptions timeSeries(TimeSeriesOptions timeSeriesOptions) {
+
+		Assert.notNull(timeSeriesOptions, "TimeSeriesOptions must not be null!");
+		return new CollectionOptions(size, maxDocuments, capped, collation, validationOptions, timeSeriesOptions);
 	}
 
 	/**
@@ -303,6 +322,16 @@ public class CollectionOptions {
 		return validationOptions.isEmpty() ? Optional.empty() : Optional.of(validationOptions);
 	}
 
+	/**
+	 * Get the {@link TimeSeriesOptions} if available.
+	 *
+	 * @return {@link Optional#empty()} if not specified.
+	 * @since 3.3
+	 */
+	public Optional<TimeSeriesOptions> getTimeSeriesOptions() {
+		return Optional.ofNullable(timeSeriesOptions);
+	}
+
 	/**
 	 * Encapsulation of ValidationOptions options.
 	 *
@@ -398,4 +427,89 @@ public class CollectionOptions {
 			return !Optionals.isAnyPresent(getValidator(), getValidationAction(), getValidationLevel());
 		}
 	}
+
+	/**
+	 * Options applicable to Time Series collections.
+	 *
+	 * @author Christoph Strobl
+	 * @since 3.3
+	 * @see <a href=
+	 *      "https://docs.mongodb.com/manual/core/timeseries-collections">https://docs.mongodb.com/manual/core/timeseries-collections</a>
+	 */
+	public static class TimeSeriesOptions {
+
+		private final String timeField;
+
+		private @Nullable final String metaField;
+
+		private final GranularityDefinition granularity;
+
+		private TimeSeriesOptions(String timeField, @Nullable String metaField, GranularityDefinition granularity) {
+
+			Assert.hasText(timeField, "Time field must not be empty or null!");
+
+			this.timeField = timeField;
+			this.metaField = metaField;
+			this.granularity = granularity;
+		}
+
+		/**
+		 * Create a new instance of {@link TimeSeriesOptions} using the given field as its {@literal timeField}. The one,
+		 * that contains the date in each time series document. <br />
+		 * {@link Field#name() Annotated fieldnames} will be considered during the mapping process.
+		 *
+		 * @param timeField must not be {@literal null}.
+		 * @return new instance of {@link TimeSeriesOptions}.
+		 */
+		public static TimeSeriesOptions timeSeries(String timeField) {
+			return new TimeSeriesOptions(timeField, null, Granularity.DEFAULT);
+		}
+
+		/**
+		 * Set the name of the field which contains metadata in each time series document. Should not be the {@literal id}
+		 * nor {@link TimeSeriesOptions#timeSeries(String)} timeField} nor point to an {@literal array} or
+		 * {@link java.util.Collection}. <br />
+		 * {@link Field#name() Annotated fieldnames} will be considered during the mapping process.
+		 *
+		 * @param metaField must not be {@literal null}.
+		 * @return new instance of {@link TimeSeriesOptions}.
+		 */
+		public TimeSeriesOptions metaField(String metaField) {
+			return new TimeSeriesOptions(timeField, metaField, granularity);
+		}
+
+		/**
+		 * Select the {@link GranularityDefinition} parameter to define how data in the time series collection is organized.
+		 * Select one that is closest to the time span between incoming measurements.
+		 *
+		 * @return new instance of {@link TimeSeriesOptions}.
+		 * @see Granularity
+		 */
+		public TimeSeriesOptions granularity(GranularityDefinition granularity) {
+			return new TimeSeriesOptions(timeField, metaField, granularity);
+		}
+
+		/**
+		 * @return never {@literal null}.
+		 */
+		public String getTimeField() {
+			return timeField;
+		}
+
+		/**
+		 * @return can be {@literal null}. Might be an {@literal empty} {@link String} as well, so maybe check via
+		 *         {@link org.springframework.util.StringUtils#hasText(String)}.
+		 */
+		@Nullable
+		public String getMetaField() {
+			return metaField;
+		}
+
+		/**
+		 * @return never {@literal null}.
+		 */
+		public GranularityDefinition getGranularity() {
+			return granularity;
+		}
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultBulkOperations.java

@@ -109,10 +109,6 @@ class DefaultBulkOperations implements BulkOperations {
 		this.defaultWriteConcern = defaultWriteConcern;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#insert(java.lang.Object)
-	 */
 	@Override
 	public BulkOperations insert(Object document) {
 
@@ -125,10 +121,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#insert(java.util.List)
-	 */
 	@Override
 	public BulkOperations insert(List<? extends Object> documents) {
 
@@ -139,10 +131,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#updateOne(org.springframework.data.mongodb.core.query.Query, org.springframework.data.mongodb.core.query.Update)
-	 */
 	@Override
 	@SuppressWarnings("unchecked")
 	public BulkOperations updateOne(Query query, Update update) {
@@ -153,10 +141,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return updateOne(Collections.singletonList(Pair.of(query, update)));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#updateOne(java.util.List)
-	 */
 	@Override
 	public BulkOperations updateOne(List<Pair<Query, Update>> updates) {
 
@@ -169,10 +153,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#updateMulti(org.springframework.data.mongodb.core.query.Query, org.springframework.data.mongodb.core.query.Update)
-	 */
 	@Override
 	@SuppressWarnings("unchecked")
 	public BulkOperations updateMulti(Query query, Update update) {
@@ -183,10 +163,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return updateMulti(Collections.singletonList(Pair.of(query, update)));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#updateMulti(java.util.List)
-	 */
 	@Override
 	public BulkOperations updateMulti(List<Pair<Query, Update>> updates) {
 
@@ -199,19 +175,11 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#upsert(org.springframework.data.mongodb.core.query.Query, org.springframework.data.mongodb.core.query.Update)
-	 */
 	@Override
 	public BulkOperations upsert(Query query, Update update) {
 		return update(query, update, true, true);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#upsert(java.util.List)
-	 */
 	@Override
 	public BulkOperations upsert(List<Pair<Query, Update>> updates) {
 
@@ -222,10 +190,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#remove(org.springframework.data.mongodb.core.query.Query)
-	 */
 	@Override
 	public BulkOperations remove(Query query) {
 
@@ -239,10 +203,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#remove(java.util.List)
-	 */
 	@Override
 	public BulkOperations remove(List<Query> removes) {
 
@@ -255,10 +215,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#replaceOne(org.springframework.data.mongodb.core.query.Query, java.lang.Object, org.springframework.data.mongodb.core.FindAndReplaceOptions)
-	 */
 	@Override
 	public BulkOperations replaceOne(Query query, Object replacement, FindAndReplaceOptions options) {
 
@@ -278,10 +234,6 @@ class DefaultBulkOperations implements BulkOperations {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.BulkOperations#executeBulk()
-	 */
 	@Override
 	public com.mongodb.bulk.BulkWriteResult execute() {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java

@@ -112,10 +112,6 @@ public class DefaultIndexOperations implements IndexOperations {
 		this.type = type;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.IndexOperations#ensureIndex(org.springframework.data.mongodb.core.index.IndexDefinition)
-	 */
 	public String ensureIndex(final IndexDefinition indexDefinition) {
 
 		return execute(collection -> {
@@ -150,10 +146,6 @@ public class DefaultIndexOperations implements IndexOperations {
 		return null;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.IndexOperations#dropIndex(java.lang.String)
-	 */
 	public void dropIndex(final String name) {
 
 		execute(collection -> {
@@ -163,18 +155,10 @@ public class DefaultIndexOperations implements IndexOperations {
 
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.IndexOperations#dropAllIndexes()
-	 */
 	public void dropAllIndexes() {
 		dropIndex("*");
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.IndexOperations#getIndexInfo()
-	 */
 	public List<IndexInfo> getIndexInfo() {
 
 		return execute(new CollectionCallback<List<IndexInfo>>() {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperationsProvider.java

@@ -42,10 +42,6 @@ class DefaultIndexOperationsProvider implements IndexOperationsProvider {
 		this.mapper = mapper;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.IndexOperationsProvider#reactiveIndexOps(java.lang.String)
-	 */
 	@Override
 	public IndexOperations indexOps(String collectionName, Class<?> type) {
 		return new DefaultIndexOperations(mongoDbFactory, collectionName, mapper, type);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultReactiveIndexOperations.java

@@ -86,10 +86,6 @@ public class DefaultReactiveIndexOperations implements ReactiveIndexOperations {
 		this.type = type;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.ReactiveIndexOperations#ensureIndex(org.springframework.data.mongodb.core.index.IndexDefinition)
-	 */
 	public Mono<String> ensureIndex(final IndexDefinition indexDefinition) {
 
 		return mongoOperations.execute(collectionName, collection -> {
@@ -119,26 +115,14 @@ public class DefaultReactiveIndexOperations implements ReactiveIndexOperations {
 				.orElse(null);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.ReactiveIndexOperations#dropIndex(java.lang.String)
-	 */
 	public Mono<Void> dropIndex(final String name) {
 		return mongoOperations.execute(collectionName, collection -> collection.dropIndex(name)).then();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.ReactiveIndexOperations#dropAllIndexes()
-	 */
 	public Mono<Void> dropAllIndexes() {
 		return dropIndex("*");
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.index.ReactiveIndexOperations#getIndexInfo()
-	 */
 	public Flux<IndexInfo> getIndexInfo() {
 
 		return mongoOperations.execute(collectionName, collection -> collection.listIndexes(Document.class)) //

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultScriptOperations.java

@@ -70,19 +70,11 @@ class DefaultScriptOperations implements ScriptOperations {
 		this.mongoOperations = mongoOperations;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#register(org.springframework.data.mongodb.core.script.ExecutableMongoScript)
-	 */
 	@Override
 	public NamedMongoScript register(ExecutableMongoScript script) {
 		return register(new NamedMongoScript(generateScriptName(), script));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#register(org.springframework.data.mongodb.core.script.NamedMongoScript)
-	 */
 	@Override
 	public NamedMongoScript register(NamedMongoScript script) {
 
@@ -92,10 +84,6 @@ class DefaultScriptOperations implements ScriptOperations {
 		return script;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#execute(org.springframework.data.mongodb.core.script.ExecutableMongoScript, java.lang.Object[])
-	 */
 	@Override
 	public Object execute(final ExecutableMongoScript script, final Object... args) {
 
@@ -115,10 +103,6 @@ class DefaultScriptOperations implements ScriptOperations {
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#call(java.lang.String, java.lang.Object[])
-	 */
 	@Override
 	public Object call(final String scriptName, final Object... args) {
 
@@ -135,10 +119,6 @@ class DefaultScriptOperations implements ScriptOperations {
 		});
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#exists(java.lang.String)
-	 */
 	@Override
 	public boolean exists(String scriptName) {
 
@@ -147,10 +127,6 @@ class DefaultScriptOperations implements ScriptOperations {
 		return mongoOperations.exists(query(where("_id").is(scriptName)), NamedMongoScript.class, SCRIPT_COLLECTION_NAME);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ScriptOperations#getScriptNames()
-	 */
 	@Override
 	public Set<String> getScriptNames() {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/EncryptionAlgorithms.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022 the original author or authors.
+ * Copyright 2021-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,17 +15,15 @@
  */
 package org.springframework.data.mongodb.core;
 
-import com.mongodb.MongoClientSettings;
-
 /**
- * A factory bean for construction of a {@link MongoClientSettings} instance to be used with the async MongoDB driver.
+ * Encryption algorithms supported by MongoDB Client Side Field Level Encryption.
  *
- * @author Mark Paluch
  * @author Christoph Strobl
- * @since 2.0
- * @deprecated since 3.0 - Use {@link MongoClientSettingsFactoryBean} instead.
+ * @since 3.3
  */
-@Deprecated
-public class ReactiveMongoClientSettingsFactoryBean extends MongoClientSettingsFactoryBean {
+public final class EncryptionAlgorithms {
+
+	public static final String AEAD_AES_256_CBC_HMAC_SHA_512_Deterministic = "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic";
+	public static final String AEAD_AES_256_CBC_HMAC_SHA_512_Random = "AEAD_AES_256_CBC_HMAC_SHA_512-Random";
 
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/EntityOperations.java

@@ -21,27 +21,45 @@ import java.util.Map;
 import java.util.Optional;
 
 import org.bson.Document;
+
 import org.springframework.core.convert.ConversionService;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.data.convert.CustomConversions;
 import org.springframework.data.mapping.IdentifierAccessor;
 import org.springframework.data.mapping.MappingException;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.model.ConvertingPropertyAccessor;
+import org.springframework.data.mongodb.core.CollectionOptions.TimeSeriesOptions;
+import org.springframework.data.mongodb.core.convert.MongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoJsonSchemaMapper;
 import org.springframework.data.mongodb.core.convert.MongoWriter;
+import org.springframework.data.mongodb.core.convert.QueryMapper;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.data.mongodb.core.mapping.MongoSimpleTypes;
+import org.springframework.data.mongodb.core.mapping.TimeSeries;
 import org.springframework.data.mongodb.core.query.Collation;
 import org.springframework.data.mongodb.core.query.Criteria;
 import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.data.mongodb.core.timeseries.Granularity;
+import org.springframework.data.mongodb.core.validation.Validator;
+import org.springframework.data.projection.EntityProjection;
+import org.springframework.data.projection.EntityProjectionIntrospector;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.util.Optionals;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.client.model.CreateCollectionOptions;
+import com.mongodb.client.model.TimeSeriesGranularity;
+import com.mongodb.client.model.ValidationOptions;
 
 /**
  * Common operations performed on an entity in the context of it's mapping metadata.
@@ -58,9 +76,31 @@ class EntityOperations {
 	private static final String ID_FIELD = "_id";
 
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context;
+	private final QueryMapper queryMapper;
 
-	EntityOperations(MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context) {
+	private final EntityProjectionIntrospector introspector;
+
+	private final MongoJsonSchemaMapper schemaMapper;
+
+	EntityOperations(MongoConverter converter) {
+		this(converter, new QueryMapper(converter));
+	}
+
+	EntityOperations(MongoConverter converter, QueryMapper queryMapper) {
+		this(converter, converter.getMappingContext(), converter.getCustomConversions(), converter.getProjectionFactory(),
+				queryMapper);
+	}
+
+	EntityOperations(MongoConverter converter,
+			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context,
+			CustomConversions conversions, ProjectionFactory projectionFactory, QueryMapper queryMapper) {
 		this.context = context;
+		this.queryMapper = queryMapper;
+		this.introspector = EntityProjectionIntrospector.create(projectionFactory,
+				EntityProjectionIntrospector.ProjectionPredicate.typeHierarchy()
+						.and(((target, underlyingType) -> !conversions.isSimpleType(target))),
+				context);
+		this.schemaMapper = new MongoJsonSchemaMapper(converter);
 	}
 
 	/**
@@ -225,6 +265,89 @@ class EntityOperations {
 		return UntypedOperations.instance();
 	}
 
+	/**
+	 * Introspect the given {@link Class result type} in the context of the {@link Class entity type} whether the returned
+	 * type is a projection and what property paths are participating in the projection.
+	 *
+	 * @param resultType the type to project on. Must not be {@literal null}.
+	 * @param entityType the source domain type. Must not be {@literal null}.
+	 * @return the introspection result.
+	 * @since 3.4
+	 * @see EntityProjectionIntrospector#introspect(Class, Class)
+	 */
+	public <M, D> EntityProjection<M, D> introspectProjection(Class<M> resultType, Class<D> entityType) {
+		return introspector.introspect(resultType, entityType);
+	}
+
+	/**
+	 * Convert {@link CollectionOptions} to {@link CreateCollectionOptions} using {@link Class entityType} to obtain
+	 * mapping metadata.
+	 *
+	 * @param collectionOptions
+	 * @param entityType
+	 * @return
+	 * @since 3.4
+	 */
+	public CreateCollectionOptions convertToCreateCollectionOptions(@Nullable CollectionOptions collectionOptions,
+			Class<?> entityType) {
+
+		Optional<Collation> collation = Optionals.firstNonEmpty(
+				() -> Optional.ofNullable(collectionOptions).flatMap(CollectionOptions::getCollation),
+				() -> forType(entityType).getCollation());//
+
+		CreateCollectionOptions result = new CreateCollectionOptions();
+		collation.map(Collation::toMongoCollation).ifPresent(result::collation);
+
+		if (collectionOptions == null) {
+			return result;
+		}
+
+		collectionOptions.getCapped().ifPresent(result::capped);
+		collectionOptions.getSize().ifPresent(result::sizeInBytes);
+		collectionOptions.getMaxDocuments().ifPresent(result::maxDocuments);
+		collectionOptions.getCollation().map(Collation::toMongoCollation).ifPresent(result::collation);
+
+		collectionOptions.getValidationOptions().ifPresent(it -> {
+
+			ValidationOptions validationOptions = new ValidationOptions();
+
+			it.getValidationAction().ifPresent(validationOptions::validationAction);
+			it.getValidationLevel().ifPresent(validationOptions::validationLevel);
+
+			it.getValidator().ifPresent(val -> validationOptions.validator(getMappedValidator(val, entityType)));
+
+			result.validationOptions(validationOptions);
+		});
+
+		collectionOptions.getTimeSeriesOptions().map(forType(entityType)::mapTimeSeriesOptions).ifPresent(it -> {
+
+			com.mongodb.client.model.TimeSeriesOptions options = new com.mongodb.client.model.TimeSeriesOptions(
+					it.getTimeField());
+
+			if (StringUtils.hasText(it.getMetaField())) {
+				options.metaField(it.getMetaField());
+			}
+			if (!Granularity.DEFAULT.equals(it.getGranularity())) {
+				options.granularity(TimeSeriesGranularity.valueOf(it.getGranularity().name().toUpperCase()));
+			}
+
+			result.timeSeriesOptions(options);
+		});
+
+		return result;
+	}
+
+	private Document getMappedValidator(Validator validator, Class<?> domainType) {
+
+		Document validationRules = validator.toDocument();
+
+		if (validationRules.containsKey("$jsonSchema")) {
+			return schemaMapper.mapSchema(validationRules, domainType);
+		}
+
+		return queryMapper.getMappedObject(validationRules, context.getPersistentEntity(domainType));
+	}
+
 	/**
 	 * A representation of information about an entity.
 	 *
@@ -369,37 +492,21 @@ class EntityOperations {
 			this.map = map;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getIdPropertyName()
-		 */
 		@Override
 		public String getIdFieldName() {
 			return ID_FIELD;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getId()
-		 */
 		@Override
 		public Object getId() {
 			return map.get(ID_FIELD);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getByIdQuery()
-		 */
 		@Override
 		public Query getByIdQuery() {
 			return Query.query(Criteria.where(ID_FIELD).is(map.get(ID_FIELD)));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.MutablePersistableSource#populateIdIfNecessary(java.lang.Object)
-		 */
 		@Nullable
 		@Override
 		public T populateIdIfNecessary(@Nullable Object id) {
@@ -409,19 +516,11 @@ class EntityOperations {
 			return map;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getQueryForVersion()
-		 */
 		@Override
 		public Query getQueryForVersion() {
 			throw new MappingException("Cannot query for version on plain Documents!");
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#toMappedDocument(org.springframework.data.mongodb.core.convert.MongoWriter)
-		 */
 		@Override
 		public MappedDocument toMappedDocument(MongoWriter<? super T> writer) {
 			return MappedDocument.of(map instanceof Document //
@@ -429,47 +528,27 @@ class EntityOperations {
 					: new Document(map));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.MutablePersistableSource#initializeVersionProperty()
-		 */
 		@Override
 		public T initializeVersionProperty() {
 			return map;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.MutablePersistableSource#getVersion()
-		 */
 		@Override
 		@Nullable
 		public Number getVersion() {
 			return null;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.MutablePersistableSource#incrementVersion()
-		 */
 		@Override
 		public T incrementVersion() {
 			return map;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getBean()
-		 */
 		@Override
 		public T getBean() {
 			return map;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.Entity#isNew()
-		 */
 		@Override
 		public boolean isNew() {
 			return map.get(ID_FIELD) != null;
@@ -482,10 +561,6 @@ class EntityOperations {
 			super(map);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#toMappedDocument(org.springframework.data.mongodb.core.convert.MongoWriter)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public MappedDocument toMappedDocument(MongoWriter<? super T> writer) {
@@ -525,28 +600,16 @@ class EntityOperations {
 			return new MappedEntity<>(entity, identifierAccessor, propertyAccessor);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getIdPropertyName()
-		 */
 		@Override
 		public String getIdFieldName() {
 			return entity.getRequiredIdProperty().getFieldName();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getId()
-		 */
 		@Override
 		public Object getId() {
 			return idAccessor.getRequiredIdentifier();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getByIdQuery()
-		 */
 		@Override
 		public Query getByIdQuery() {
 
@@ -559,10 +622,6 @@ class EntityOperations {
 			return Query.query(Criteria.where(idProperty.getName()).is(getId()));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getQueryForVersion(java.lang.Object)
-		 */
 		@Override
 		public Query getQueryForVersion() {
 
@@ -573,10 +632,6 @@ class EntityOperations {
 					.and(versionProperty.getName()).is(getVersion()));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#toMappedDocument(org.springframework.data.mongodb.core.convert.MongoWriter)
-		 */
 		@Override
 		public MappedDocument toMappedDocument(MongoWriter<? super T> writer) {
 
@@ -592,10 +647,6 @@ class EntityOperations {
 			return MappedDocument.of(document);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.Entity#assertUpdateableIdIfNotSet()
-		 */
 		public void assertUpdateableIdIfNotSet() {
 
 			if (!entity.hasIdProperty()) {
@@ -616,38 +667,22 @@ class EntityOperations {
 			}
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#isVersionedEntity()
-		 */
 		@Override
 		public boolean isVersionedEntity() {
 			return entity.hasVersionProperty();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getVersion()
-		 */
 		@Override
 		@Nullable
 		public Object getVersion() {
 			return propertyAccessor.getProperty(entity.getRequiredVersionProperty());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.PersistableSource#getBean()
-		 */
 		@Override
 		public T getBean() {
 			return propertyAccessor.getBean();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.Entity#isNew()
-		 */
 		@Override
 		public boolean isNew() {
 			return entity.isNew(propertyAccessor.getBean());
@@ -682,10 +717,6 @@ class EntityOperations {
 					new ConvertingPropertyAccessor<>(propertyAccessor, conversionService));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity#populateIdIfNecessary(java.lang.Object)
-		 */
 		@Nullable
 		@Override
 		public T populateIdIfNecessary(@Nullable Object id) {
@@ -707,10 +738,6 @@ class EntityOperations {
 			return propertyAccessor.getBean();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.MappedEntity#getVersion()
-		 */
 		@Override
 		@Nullable
 		public Number getVersion() {
@@ -720,10 +747,6 @@ class EntityOperations {
 			return propertyAccessor.getProperty(versionProperty, Number.class);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity#initializeVersionProperty()
-		 */
 		@Override
 		public T initializeVersionProperty() {
 
@@ -738,10 +761,6 @@ class EntityOperations {
 			return propertyAccessor.getBean();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity#incrementVersion()
-		 */
 		@Override
 		public T incrementVersion() {
 
@@ -778,6 +797,24 @@ class EntityOperations {
 		 * @return
 		 */
 		Optional<Collation> getCollation(Query query);
+
+		/**
+		 * Derive the applicable {@link CollectionOptions} for the given type.
+		 *
+		 * @return never {@literal null}.
+		 * @since 3.3
+		 */
+		CollectionOptions getCollectionOptions();
+
+		/**
+		 * Map the fields of a given {@link TimeSeriesOptions} against the target domain type to consider potentially
+		 * annotated field names.
+		 *
+		 * @param options must not be {@literal null}.
+		 * @return never {@literal null}.
+		 * @since 3.3
+		 */
+		TimeSeriesOptions mapTimeSeriesOptions(TimeSeriesOptions options);
 	}
 
 	/**
@@ -795,19 +832,11 @@ class EntityOperations {
 			return (TypedOperations) INSTANCE;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.TypedOperations#getCollation()
-		 */
 		@Override
 		public Optional<Collation> getCollation() {
 			return Optional.empty();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.TypedOperations#getCollation(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public Optional<Collation> getCollation(Query query) {
 
@@ -817,6 +846,16 @@ class EntityOperations {
 
 			return query.getCollation();
 		}
+
+		@Override
+		public CollectionOptions getCollectionOptions() {
+			return CollectionOptions.empty();
+		}
+
+		@Override
+		public TimeSeriesOptions mapTimeSeriesOptions(TimeSeriesOptions options) {
+			return options;
+		}
 	}
 
 	/**
@@ -832,19 +871,11 @@ class EntityOperations {
 			this.entity = entity;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.TypedOperations#getCollation()
-		 */
 		@Override
 		public Optional<Collation> getCollation() {
 			return Optional.ofNullable(entity.getCollation());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.EntityOperations.TypedOperations#getCollation(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public Optional<Collation> getCollation(Query query) {
 
@@ -854,6 +885,58 @@ class EntityOperations {
 
 			return Optional.ofNullable(entity.getCollation());
 		}
+
+		@Override
+		public CollectionOptions getCollectionOptions() {
+
+			CollectionOptions collectionOptions = CollectionOptions.empty();
+			if (entity.hasCollation()) {
+				collectionOptions = collectionOptions.collation(entity.getCollation());
+			}
+
+			if (entity.isAnnotationPresent(TimeSeries.class)) {
+
+				TimeSeries timeSeries = entity.getRequiredAnnotation(TimeSeries.class);
+
+				if (entity.getPersistentProperty(timeSeries.timeField()) == null) {
+					throw new MappingException(String.format("Time series field '%s' does not exist in type %s",
+							timeSeries.timeField(), entity.getName()));
+				}
+
+				TimeSeriesOptions options = TimeSeriesOptions.timeSeries(timeSeries.timeField());
+				if (StringUtils.hasText(timeSeries.metaField())) {
+
+					if (entity.getPersistentProperty(timeSeries.metaField()) == null) {
+						throw new MappingException(
+								String.format("Meta field '%s' does not exist in type %s", timeSeries.metaField(), entity.getName()));
+					}
+
+					options = options.metaField(timeSeries.metaField());
+				}
+				if (!Granularity.DEFAULT.equals(timeSeries.granularity())) {
+					options = options.granularity(timeSeries.granularity());
+				}
+				collectionOptions = collectionOptions.timeSeries(options);
+			}
+
+			return collectionOptions;
+		}
+
+		@Override
+		public TimeSeriesOptions mapTimeSeriesOptions(TimeSeriesOptions source) {
+
+			TimeSeriesOptions target = TimeSeriesOptions.timeSeries(mappedNameOrDefault(source.getTimeField()));
+
+			if (StringUtils.hasText(source.getMetaField())) {
+				target = target.metaField(mappedNameOrDefault(source.getMetaField()));
+			}
+			return target.granularity(source.getGranularity());
+		}
+
+		private String mappedNameOrDefault(String name) {
+			MongoPersistentProperty persistentProperty = entity.getPersistentProperty(name);
+			return persistentProperty != null ? persistentProperty.getFieldName() : name;
+		}
 	}
 
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableAggregationOperation.java

@@ -15,9 +15,10 @@
  */
 package org.springframework.data.mongodb.core;
 
+import java.util.stream.Stream;
+
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.aggregation.AggregationResults;
-import org.springframework.data.util.CloseableIterator;
 
 /**
  * {@link ExecutableAggregationOperation} allows creation and execution of MongoDB aggregation operations in a fluent
@@ -88,12 +89,12 @@ public interface ExecutableAggregationOperation {
 
 		/**
 		 * Apply pipeline operations as specified and stream all matching elements. <br />
-		 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable}
+		 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.FindIterable}
 		 *
-		 * @return a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
-		 *         Never {@literal null}.
+		 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+		 *         through a try-with-resources clause).
 		 */
-		CloseableIterator<T> stream();
+		Stream<T> stream();
 	}
 
 	/**

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableAggregationOperationSupport.java

@@ -15,10 +15,11 @@
  */
 package org.springframework.data.mongodb.core;
 
+import java.util.stream.Stream;
+
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.aggregation.AggregationResults;
 import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
-import org.springframework.data.util.CloseableIterator;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -37,10 +38,6 @@ class ExecutableAggregationOperationSupport implements ExecutableAggregationOper
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation#aggregateAndReturn(java.lang.Class)
-	 */
 	@Override
 	public <T> ExecutableAggregation<T> aggregateAndReturn(Class<T> domainType) {
 
@@ -69,10 +66,6 @@ class ExecutableAggregationOperationSupport implements ExecutableAggregationOper
 			this.collection = collection;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation.AggregationWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public AggregationWithAggregation<T> inCollection(String collection) {
 
@@ -81,10 +74,6 @@ class ExecutableAggregationOperationSupport implements ExecutableAggregationOper
 			return new ExecutableAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation.AggregationWithAggregation#by(org.springframework.data.mongodb.core.aggregation.Aggregation)
-		 */
 		@Override
 		public TerminatingAggregation<T> by(Aggregation aggregation) {
 
@@ -93,21 +82,13 @@ class ExecutableAggregationOperationSupport implements ExecutableAggregationOper
 			return new ExecutableAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation.TerminatingAggregation#all()
-		 */
 		@Override
 		public AggregationResults<T> all() {
 			return template.aggregate(aggregation, getCollectionName(aggregation), domainType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation.TerminatingAggregation#stream()
-		 */
 		@Override
-		public CloseableIterator<T> stream() {
+		public Stream<T> stream() {
 			return template.aggregateStream(aggregation, getCollectionName(aggregation), domainType);
 		}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableFindOperation.java

@@ -118,8 +118,8 @@ public interface ExecutableFindOperation {
 		/**
 		 * Stream all matching elements.
 		 *
-		 * @return a {@link Stream} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed. Never
-		 *         {@literal null}.
+		 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+		 *         through a try-with-resources clause).
 		 */
 		Stream<T> stream();
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableFindOperationSupport.java

@@ -20,12 +20,11 @@ import java.util.Optional;
 import java.util.stream.Stream;
 
 import org.bson.Document;
+
 import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.data.mongodb.core.query.NearQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.SerializationUtils;
-import org.springframework.data.util.CloseableIterator;
-import org.springframework.data.util.StreamUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
@@ -51,10 +50,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ExecutableFindOperation#query(java.lang.Class)
-	 */
 	@Override
 	public <T> ExecutableFind<T> query(Class<T> domainType) {
 
@@ -74,11 +69,11 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 		private final MongoTemplate template;
 		private final Class<?> domainType;
 		private final Class<T> returnType;
-		@Nullable private final String collection;
+		private final @Nullable String collection;
 		private final Query query;
 
 		ExecutableFindSupport(MongoTemplate template, Class<?> domainType, Class<T> returnType,
-				String collection, Query query) {
+				@Nullable String collection, Query query) {
 			this.template = template;
 			this.domainType = domainType;
 			this.returnType = returnType;
@@ -86,10 +81,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			this.query = query;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.FindWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public FindWithProjection<T> inCollection(String collection) {
 
@@ -98,10 +89,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return new ExecutableFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.FindWithProjection#as(Class)
-		 */
 		@Override
 		public <T1> FindWithQuery<T1> as(Class<T1> returnType) {
 
@@ -110,10 +97,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return new ExecutableFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.FindWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public TerminatingFind<T> matching(Query query) {
 
@@ -122,10 +105,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return new ExecutableFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#oneValue()
-		 */
 		@Override
 		public T oneValue() {
 
@@ -142,10 +121,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return result.iterator().next();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#firstValue()
-		 */
 		@Override
 		public T firstValue() {
 
@@ -154,55 +129,31 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return ObjectUtils.isEmpty(result) ? null : result.iterator().next();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#all()
-		 */
 		@Override
 		public List<T> all() {
 			return doFind(null);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#stream()
-		 */
 		@Override
 		public Stream<T> stream() {
-			return StreamUtils.createStreamFromIterator(doStream());
+			return doStream();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.FindWithQuery#near(org.springframework.data.mongodb.core.query.NearQuery)
-		 */
 		@Override
 		public TerminatingFindNear<T> near(NearQuery nearQuery) {
 			return () -> template.geoNear(nearQuery, domainType, getCollectionName(), returnType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#count()
-		 */
 		@Override
 		public long count() {
 			return template.count(query, domainType, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#exists()
-		 */
 		@Override
 		public boolean exists() {
 			return template.exists(query, domainType, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.FindDistinct#distinct(java.lang.String)
-		 */
 		@SuppressWarnings("unchecked")
 		@Override
 		public TerminatingDistinct<Object> distinct(String field) {
@@ -227,7 +178,7 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 					returnType == domainType ? (Class<T>) Object.class : returnType);
 		}
 
-		private CloseableIterator<T> doStream() {
+		private Stream<T> doStream() {
 			return template.doStream(query, domainType, getCollectionName(), returnType);
 		}
 
@@ -257,10 +208,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			this.delegate = delegate;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.CursorPreparer#prepare(com.mongodb.clientFindIterable)
-		 */
 		@Override
 		public FindIterable<Document> prepare(FindIterable<Document> iterable) {
 
@@ -295,10 +242,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			this.field = field;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.DistinctWithProjection#as(java.lang.Class)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public <R> TerminatingDistinct<R> as(Class<R> resultType) {
@@ -308,10 +251,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return new DistinctOperationSupport<>((ExecutableFindSupport) delegate.as(resultType), field);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.DistinctWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public TerminatingDistinct<T> matching(Query query) {
 
@@ -320,10 +259,6 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return new DistinctOperationSupport<>((ExecutableFindSupport<T>) delegate.matching(query), field);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingDistinct#all()
-		 */
 		@Override
 		public List<T> all() {
 			return delegate.doFindDistinct(field);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableInsertOperationSupport.java

@@ -40,10 +40,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.coreExecutableInsertOperation#insert(java.lan.Class)
-	 */
 	@Override
 	public <T> ExecutableInsert<T> insert(Class<T> domainType) {
 
@@ -71,10 +67,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 			this.bulkMode = bulkMode;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation.TerminatingInsert#insert(java.lang.Class)
-		 */
 		@Override
 		public T one(T object) {
 
@@ -83,10 +75,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 			return template.insert(object, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation.TerminatingInsert#all(java.util.Collection)
-		 */
 		@Override
 		public Collection<T> all(Collection<? extends T> objects) {
 
@@ -95,10 +83,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 			return template.insert(objects, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation.TerminatingBulkInsert#bulk(java.util.Collection)
-		 */
 		@Override
 		public BulkWriteResult bulk(Collection<? extends T> objects) {
 
@@ -108,10 +92,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 					.insert(new ArrayList<>(objects)).execute();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation.InsertWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public InsertWithBulkMode<T> inCollection(String collection) {
 
@@ -120,10 +100,6 @@ class ExecutableInsertOperationSupport implements ExecutableInsertOperation {
 			return new ExecutableInsertSupport<>(template, domainType, collection, bulkMode);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation.InsertWithBulkMode#withBulkMode(org.springframework.data.mongodb.core.BulkMode)
-		 */
 		@Override
 		public TerminatingBulkInsert<T> withBulkMode(BulkMode bulkMode) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableRemoveOperationSupport.java

@@ -41,10 +41,6 @@ class ExecutableRemoveOperationSupport implements ExecutableRemoveOperation {
 		this.tempate = tempate;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation#remove(java.lang.Class)
-	 */
 	@Override
 	public <T> ExecutableRemove<T> remove(Class<T> domainType) {
 
@@ -71,10 +67,6 @@ class ExecutableRemoveOperationSupport implements ExecutableRemoveOperation {
 			this.collection = collection;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation.RemoveWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public RemoveWithQuery<T> inCollection(String collection) {
 
@@ -83,10 +75,6 @@ class ExecutableRemoveOperationSupport implements ExecutableRemoveOperation {
 			return new ExecutableRemoveSupport<>(template, domainType, query, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation.RemoveWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public TerminatingRemove<T> matching(Query query) {
 
@@ -95,28 +83,16 @@ class ExecutableRemoveOperationSupport implements ExecutableRemoveOperation {
 			return new ExecutableRemoveSupport<>(template, domainType, query, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation.TerminatingRemove#all()
-		 */
 		@Override
 		public DeleteResult all() {
 			return template.doRemove(getCollectionName(), query, domainType, true);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation.TerminatingRemove#one()
-		 */
 		@Override
 		public DeleteResult one() {
 			return template.doRemove(getCollectionName(), query, domainType, false);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableRemoveOperation.TerminatingRemove#findAndRemove()
-		 */
 		@Override
 		public List<T> findAndRemove() {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableUpdateOperationSupport.java

@@ -40,10 +40,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation#update(java.lang.Class)
-	 */
 	@Override
 	public <T> ExecutableUpdate<T> update(Class<T> domainType) {
 
@@ -85,10 +81,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 			this.targetType = targetType;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.UpdateWithUpdate#apply(org.springframework.data.mongodb.core.query.UpdateDefinition)
-		 */
 		@Override
 		public TerminatingUpdate<T> apply(UpdateDefinition update) {
 
@@ -98,10 +90,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.UpdateWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public UpdateWithQuery<T> inCollection(String collection) {
 
@@ -111,10 +99,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.FindAndModifyWithOptions#withOptions(org.springframework.data.mongodb.core.FindAndModifyOptions)
-		 */
 		@Override
 		public TerminatingFindAndModify<T> withOptions(FindAndModifyOptions options) {
 
@@ -124,10 +108,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.UpdateWithUpdate#replaceWith(Object)
-		 */
 		@Override
 		public FindAndReplaceWithProjection<T> replaceWith(T replacement) {
 
@@ -137,10 +117,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.FindAndReplaceWithOptions#withOptions(org.springframework.data.mongodb.core.FindAndReplaceOptions)
-		 */
 		@Override
 		public FindAndReplaceWithProjection<T> withOptions(FindAndReplaceOptions options) {
 
@@ -150,10 +126,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					options, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.UpdateWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public UpdateWithUpdate<T> matching(Query query) {
 
@@ -163,10 +135,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.FindAndReplaceWithProjection#as(java.lang.Class)
-		 */
 		@Override
 		public <R> FindAndReplaceWithOptions<R> as(Class<R> resultType) {
 
@@ -176,37 +144,21 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					findAndReplaceOptions, replacement, resultType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.TerminatingUpdate#all()
-		 */
 		@Override
 		public UpdateResult all() {
 			return doUpdate(true, false);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.TerminatingUpdate#first()
-		 */
 		@Override
 		public UpdateResult first() {
 			return doUpdate(false, false);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.TerminatingUpdate#upsert()
-		 */
 		@Override
 		public UpdateResult upsert() {
 			return doUpdate(true, true);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.TerminatingFindAndModify#findAndModifyValue()
-		 */
 		@Override
 		public @Nullable T findAndModifyValue() {
 
@@ -215,10 +167,6 @@ class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 					getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ExecutableUpdateOperation.TerminatingFindAndReplace#findAndReplaceValue()
-		 */
 		@Override
 		public @Nullable T findAndReplaceValue() {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/IndexConverters.java

@@ -115,6 +115,10 @@ abstract class IndexConverters {
 				ops = ops.collation(fromDocument(indexOptions.get("collation", Document.class)));
 			}
 
+			if (indexOptions.containsKey("wildcardProjection")) {
+				ops.wildcardProjection(indexOptions.get("wildcardProjection", Document.class));
+			}
+
 			return ops;
 		};
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MappedDocument.java

@@ -112,55 +112,31 @@ public class MappedDocument {
 			this.delegate = delegate;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#getUpdateObject()
-		 */
 		@Override
 		public Document getUpdateObject() {
 			return delegate.getUpdateObject();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#modifies(java.lang.String)
-		 */
 		@Override
 		public boolean modifies(String key) {
 			return delegate.modifies(key);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#inc(java.lang.String)
-		 */
 		@Override
 		public void inc(String version) {
 			delegate.inc(version);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#isIsolated()
-		 */
 		@Override
 		public Boolean isIsolated() {
 			return delegate.isIsolated();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#getArrayFilters()
-		 */
 		@Override
 		public List<ArrayFilter> getArrayFilters() {
 			return delegate.getArrayFilters();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#hasArrayFilters()
-		 */
 		@Override
 		public boolean hasArrayFilters() {
 			return delegate.hasArrayFilters();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MappingMongoJsonSchemaCreator.java

@@ -20,13 +20,19 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
+import org.bson.Document;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
+import org.springframework.data.mongodb.core.mapping.Encrypted;
 import org.springframework.data.mongodb.core.mapping.Field;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.schema.IdentifiableJsonSchemaProperty.ArrayJsonSchemaProperty;
+import org.springframework.data.mongodb.core.schema.IdentifiableJsonSchemaProperty.EncryptedJsonSchemaProperty;
 import org.springframework.data.mongodb.core.schema.IdentifiableJsonSchemaProperty.ObjectJsonSchemaProperty;
 import org.springframework.data.mongodb.core.schema.JsonSchemaObject;
 import org.springframework.data.mongodb.core.schema.JsonSchemaObject.Type;
@@ -34,10 +40,13 @@ import org.springframework.data.mongodb.core.schema.JsonSchemaProperty;
 import org.springframework.data.mongodb.core.schema.MongoJsonSchema;
 import org.springframework.data.mongodb.core.schema.MongoJsonSchema.MongoJsonSchemaBuilder;
 import org.springframework.data.mongodb.core.schema.TypedJsonSchemaObject;
+import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
+import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
 
 /**
  * {@link MongoJsonSchemaCreator} implementation using both {@link MongoConverter} and {@link MappingContext} to obtain
@@ -52,6 +61,8 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 
 	private final MongoConverter converter;
 	private final MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
+	private final Predicate<JsonSchemaPropertyContext> filter;
+	private final LinkedMultiValueMap<String, Class<?>> mergeProperties;
 
 	/**
 	 * Create a new instance of {@link MappingMongoJsonSchemaCreator}.
@@ -61,27 +72,78 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 	@SuppressWarnings("unchecked")
 	MappingMongoJsonSchemaCreator(MongoConverter converter) {
 
-		Assert.notNull(converter, "Converter must not be null!");
-		this.converter = converter;
-		this.mappingContext = (MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty>) converter
-				.getMappingContext();
+		this(converter, (MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty>) converter.getMappingContext(),
+				(property) -> true, new LinkedMultiValueMap<>());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * org.springframework.data.mongodb.core.MongoJsonSchemaCreator#createSchemaFor(java.lang.Class)
+	@SuppressWarnings("unchecked")
+	MappingMongoJsonSchemaCreator(MongoConverter converter,
+			MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext,
+			Predicate<JsonSchemaPropertyContext> filter, LinkedMultiValueMap<String, Class<?>> mergeProperties) {
+
+		Assert.notNull(converter, "Converter must not be null!");
+		this.converter = converter;
+		this.mappingContext = mappingContext;
+		this.filter = filter;
+		this.mergeProperties = mergeProperties;
+	}
+
+	@Override
+	public MongoJsonSchemaCreator filter(Predicate<JsonSchemaPropertyContext> filter) {
+		return new MappingMongoJsonSchemaCreator(converter, mappingContext, filter, mergeProperties);
+	}
+
+	@Override
+	public PropertySpecifier property(String path) {
+		return types -> withTypesFor(path, types);
+	}
+
+	/**
+	 * Specify additional types to be considered wehen rendering the schema for the given path.
+	 *
+	 * @param path path the path using {@literal dot '.'} notation.
+	 * @param types must not be {@literal null}.
+	 * @return new instance of {@link MongoJsonSchemaCreator}.
+	 * @since 3.4
 	 */
+	public MongoJsonSchemaCreator withTypesFor(String path, Class<?>... types) {
+
+		LinkedMultiValueMap<String, Class<?>> clone = mergeProperties.clone();
+		for (Class<?> type : types) {
+			clone.add(path, type);
+		}
+		return new MappingMongoJsonSchemaCreator(converter, mappingContext, filter, clone);
+	}
+
 	@Override
 	public MongoJsonSchema createSchemaFor(Class<?> type) {
 
 		MongoPersistentEntity<?> entity = mappingContext.getRequiredPersistentEntity(type);
 		MongoJsonSchemaBuilder schemaBuilder = MongoJsonSchema.builder();
 
+		{
+			Encrypted encrypted = entity.findAnnotation(Encrypted.class);
+			if (encrypted != null) {
+
+				Document encryptionMetadata = new Document();
+
+				Collection<Object> encryptionKeyIds = entity.getEncryptionKeyIds();
+				if (!CollectionUtils.isEmpty(encryptionKeyIds)) {
+					encryptionMetadata.append("keyId", encryptionKeyIds);
+				}
+
+				if (StringUtils.hasText(encrypted.algorithm())) {
+					encryptionMetadata.append("algorithm", encrypted.algorithm());
+				}
+
+				schemaBuilder.encryptionMetadata(encryptionMetadata);
+			}
+		}
+
 		List<JsonSchemaProperty> schemaProperties = computePropertiesForEntity(Collections.emptyList(), entity);
 		schemaBuilder.properties(schemaProperties.toArray(new JsonSchemaProperty[0]));
 
 		return schemaBuilder.build();
-
 	}
 
 	private List<JsonSchemaProperty> computePropertiesForEntity(List<MongoPersistentProperty> path,
@@ -93,6 +155,14 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 
 			List<MongoPersistentProperty> currentPath = new ArrayList<>(path);
 
+			String stringPath = currentPath.stream().map(PersistentProperty::getName).collect(Collectors.joining("."));
+			stringPath = StringUtils.hasText(stringPath) ? (stringPath + "." + nested.getName()) : nested.getName();
+			if (!filter.test(new PropertyContext(stringPath, nested))) {
+				if (!mergeProperties.containsKey(stringPath)) {
+					continue;
+				}
+			}
+
 			if (path.contains(nested)) { // cycle guard
 				schemaProperties.add(createSchemaProperty(computePropertyFieldName(CollectionUtils.lastElement(currentPath)),
 						Object.class, false));
@@ -108,27 +178,114 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 
 	private JsonSchemaProperty computeSchemaForProperty(List<MongoPersistentProperty> path) {
 
+		String stringPath = path.stream().map(MongoPersistentProperty::getName).collect(Collectors.joining("."));
 		MongoPersistentProperty property = CollectionUtils.lastElement(path);
 
 		boolean required = isRequiredProperty(property);
 		Class<?> rawTargetType = computeTargetType(property); // target type before conversion
 		Class<?> targetType = converter.getTypeMapper().getWriteTargetTypeFor(rawTargetType); // conversion target type
 
-		if (property.isEntity() && ObjectUtils.nullSafeEquals(rawTargetType, targetType)) {
-			return createObjectSchemaPropertyForEntity(path, property, required);
+		if (!isCollection(property) && ObjectUtils.nullSafeEquals(rawTargetType, targetType)) {
+			if (property.isEntity() || mergeProperties.containsKey(stringPath)) {
+				List<JsonSchemaProperty> targetProperties = new ArrayList<>();
+
+				if (property.isEntity()) {
+					targetProperties.add(createObjectSchemaPropertyForEntity(path, property, required));
+				}
+				if (mergeProperties.containsKey(stringPath)) {
+					for (Class<?> theType : mergeProperties.get(stringPath)) {
+
+						ObjectJsonSchemaProperty target = JsonSchemaProperty.object(property.getName());
+						List<JsonSchemaProperty> nestedProperties = computePropertiesForEntity(path,
+								mappingContext.getRequiredPersistentEntity(theType));
+
+						targetProperties.add(createPotentiallyRequiredSchemaProperty(
+								target.properties(nestedProperties.toArray(new JsonSchemaProperty[0])), required));
+					}
+				}
+				return targetProperties.size() == 1 ? targetProperties.iterator().next()
+						: JsonSchemaProperty.merged(targetProperties);
+			}
 		}
 
 		String fieldName = computePropertyFieldName(property);
 
-		if (property.isCollectionLike()) {
-			return createSchemaProperty(fieldName, targetType, required);
+		JsonSchemaProperty schemaProperty;
+		if (isCollection(property)) {
+			schemaProperty = createArraySchemaProperty(fieldName, property, required);
 		} else if (property.isMap()) {
-			return createSchemaProperty(fieldName, Type.objectType(), required);
+			schemaProperty = createSchemaProperty(fieldName, Type.objectType(), required);
 		} else if (ClassUtils.isAssignable(Enum.class, targetType)) {
-			return createEnumSchemaProperty(fieldName, targetType, required);
+			schemaProperty = createEnumSchemaProperty(fieldName, targetType, required);
+		} else {
+			schemaProperty = createSchemaProperty(fieldName, targetType, required);
 		}
 
-		return createSchemaProperty(fieldName, targetType, required);
+		return applyEncryptionDataIfNecessary(property, schemaProperty);
+	}
+
+	private JsonSchemaProperty createArraySchemaProperty(String fieldName, MongoPersistentProperty property,
+			boolean required) {
+
+		ArrayJsonSchemaProperty schemaProperty = JsonSchemaProperty.array(fieldName);
+
+		if (isSpecificType(property)) {
+			schemaProperty = potentiallyEnhanceArraySchemaProperty(property, schemaProperty);
+		}
+
+		return createPotentiallyRequiredSchemaProperty(schemaProperty, required);
+	}
+
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	private ArrayJsonSchemaProperty potentiallyEnhanceArraySchemaProperty(MongoPersistentProperty property,
+			ArrayJsonSchemaProperty schemaProperty) {
+
+		MongoPersistentEntity<?> persistentEntity = mappingContext
+				.getPersistentEntity(property.getTypeInformation().getRequiredComponentType());
+
+		if (persistentEntity != null) {
+
+			List<JsonSchemaProperty> nestedProperties = computePropertiesForEntity(Collections.emptyList(), persistentEntity);
+
+			if (nestedProperties.isEmpty()) {
+				return schemaProperty;
+			}
+
+			return schemaProperty
+					.items(JsonSchemaObject.object().properties(nestedProperties.toArray(new JsonSchemaProperty[0])));
+		}
+
+		if (ClassUtils.isAssignable(Enum.class, property.getActualType())) {
+
+			List<Object> possibleValues = getPossibleEnumValues((Class<Enum>) property.getActualType());
+
+			return schemaProperty
+					.items(createSchemaObject(computeTargetType(property.getActualType(), possibleValues), possibleValues));
+		}
+
+		return schemaProperty.items(JsonSchemaObject.of(property.getActualType()));
+	}
+
+	private boolean isSpecificType(MongoPersistentProperty property) {
+		return !ClassTypeInformation.OBJECT.equals(property.getTypeInformation().getActualType());
+	}
+
+	private JsonSchemaProperty applyEncryptionDataIfNecessary(MongoPersistentProperty property,
+			JsonSchemaProperty schemaProperty) {
+
+		Encrypted encrypted = property.findAnnotation(Encrypted.class);
+		if (encrypted == null) {
+			return schemaProperty;
+		}
+
+		EncryptedJsonSchemaProperty enc = new EncryptedJsonSchemaProperty(schemaProperty);
+		if (StringUtils.hasText(encrypted.algorithm())) {
+			enc = enc.algorithm(encrypted.algorithm());
+		}
+		if (!ObjectUtils.isEmpty(encrypted.keyId())) {
+			enc = enc.keys(property.getEncryptionKeyIds());
+		}
+		return enc;
 	}
 
 	private JsonSchemaProperty createObjectSchemaPropertyForEntity(List<MongoPersistentProperty> path,
@@ -142,15 +299,12 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 				target.properties(nestedProperties.toArray(new JsonSchemaProperty[0])), required);
 	}
 
+	@SuppressWarnings({ "unchecked", "rawtypes" })
 	private JsonSchemaProperty createEnumSchemaProperty(String fieldName, Class<?> targetType, boolean required) {
 
-		List<Object> possibleValues = new ArrayList<>();
+		List<Object> possibleValues = getPossibleEnumValues((Class<Enum>) targetType);
 
-		for (Object enumValue : EnumSet.allOf((Class) targetType)) {
-			possibleValues.add(converter.convertToMongoType(enumValue));
-		}
-
-		targetType = possibleValues.isEmpty() ? targetType : possibleValues.iterator().next().getClass();
+		targetType = computeTargetType(targetType, possibleValues);
 		return createSchemaProperty(fieldName, targetType, required, possibleValues);
 	}
 
@@ -161,14 +315,20 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 	JsonSchemaProperty createSchemaProperty(String fieldName, Object type, boolean required,
 			Collection<?> possibleValues) {
 
+		TypedJsonSchemaObject schemaObject = createSchemaObject(type, possibleValues);
+
+		return createPotentiallyRequiredSchemaProperty(JsonSchemaProperty.named(fieldName).with(schemaObject), required);
+	}
+
+	private TypedJsonSchemaObject createSchemaObject(Object type, Collection<?> possibleValues) {
+
 		TypedJsonSchemaObject schemaObject = type instanceof Type ? JsonSchemaObject.of(Type.class.cast(type))
 				: JsonSchemaObject.of(Class.class.cast(type));
 
 		if (!CollectionUtils.isEmpty(possibleValues)) {
 			schemaObject = schemaObject.possibleValues(possibleValues);
 		}
-
-		return createPotentiallyRequiredSchemaProperty(JsonSchemaProperty.named(fieldName).with(schemaObject), required);
+		return schemaObject;
 	}
 
 	private String computePropertyFieldName(PersistentProperty property) {
@@ -199,12 +359,53 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 		return mongoProperty.getFieldType() != mongoProperty.getActualType() ? Object.class : mongoProperty.getFieldType();
 	}
 
-	static JsonSchemaProperty createPotentiallyRequiredSchemaProperty(JsonSchemaProperty property, boolean required) {
+	private static Class<?> computeTargetType(Class<?> fallback, List<Object> possibleValues) {
+		return possibleValues.isEmpty() ? fallback : possibleValues.iterator().next().getClass();
+	}
 
-		if (!required) {
+	private <E extends Enum<E>> List<Object> getPossibleEnumValues(Class<E> targetType) {
+
+		EnumSet<E> enumSet = EnumSet.allOf(targetType);
+		List<Object> possibleValues = new ArrayList<>(enumSet.size());
+
+		for (Object enumValue : enumSet) {
+			possibleValues.add(converter.convertToMongoType(enumValue));
+		}
+
+		return possibleValues;
+	}
+
+	private static boolean isCollection(MongoPersistentProperty property) {
+		return property.isCollectionLike() && !property.getType().equals(byte[].class);
+	}
+
+	static JsonSchemaProperty createPotentiallyRequiredSchemaProperty(JsonSchemaProperty property, boolean required) {
+		return required ? JsonSchemaProperty.required(property) : property;
+	}
+
+	class PropertyContext implements JsonSchemaPropertyContext {
+
+		private final String path;
+		private final MongoPersistentProperty property;
+
+		public PropertyContext(String path, MongoPersistentProperty property) {
+			this.path = path;
+			this.property = property;
+		}
+
+		@Override
+		public String getPath() {
+			return path;
+		}
+
+		@Override
+		public MongoPersistentProperty getProperty() {
 			return property;
 		}
 
-		return JsonSchemaProperty.required(property);
+		@Override
+		public <T> MongoPersistentEntity<T> resolveEntity(MongoPersistentProperty property) {
+			return (MongoPersistentEntity<T>) mappingContext.getPersistentEntity(property);
+		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java

@@ -46,25 +46,16 @@ public class MongoAdmin implements MongoAdminOperations {
 		this.mongoClient = client;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.core.MongoAdminOperations#dropDatabase(java.lang.String)
-	 */
 	@ManagedOperation
 	public void dropDatabase(String databaseName) {
 		getDB(databaseName).drop();
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.core.MongoAdminOperations#createDatabase(java.lang.String)
-	 */
 	@ManagedOperation
 	public void createDatabase(String databaseName) {
 		getDB(databaseName);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.core.MongoAdminOperations#getDatabaseStats(java.lang.String)
-	 */
 	@ManagedOperation
 	public String getDatabaseStats(String databaseName) {
 		return getDB(databaseName).runCommand(new Document("dbStats", 1).append("scale", 1024)).toJson();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoClientFactoryBean.java

@@ -119,27 +119,15 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 		this.exceptionTranslator = exceptionTranslator == null ? DEFAULT_EXCEPTION_TRANSLATOR : exceptionTranslator;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.FactoryBean#getObjectType()
-	 */
 	public Class<? extends MongoClient> getObjectType() {
 		return MongoClient.class;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.dao.support.PersistenceExceptionTranslator#translateExceptionIfPossible(java.lang.RuntimeException)
-	 */
 	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		return exceptionTranslator.translateExceptionIfPossible(ex);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.config.AbstractFactoryBean#createInstance()
-	 */
 	@Override
 	protected MongoClient createInstance() throws Exception {
 		return createMongoClient(computeClientSetting());
@@ -336,10 +324,6 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 		return !fromConnectionStringIsDefault ? fromConnectionString : defaultValue;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.config.AbstractFactoryBean#destroyInstance(java.lang.Object)
-	 */
 	@Override
 	protected void destroyInstance(@Nullable MongoClient instance) throws Exception {
 
@@ -353,6 +337,11 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 	}
 
 	private String getOrDefault(Object value, String defaultValue) {
-		return !StringUtils.isEmpty(value) ? value.toString() : defaultValue;
+
+		if(value == null) {
+			return defaultValue;
+		}
+		String sValue = value.toString();
+		return StringUtils.hasText(sValue) ? sValue : defaultValue;
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoClientSettingsFactoryBean.java

@@ -36,6 +36,7 @@ import com.mongodb.MongoClientSettings.Builder;
 import com.mongodb.ReadConcern;
 import com.mongodb.ReadPreference;
 import com.mongodb.ServerAddress;
+import com.mongodb.ServerApi;
 import com.mongodb.WriteConcern;
 import com.mongodb.connection.ClusterConnectionMode;
 import com.mongodb.connection.ClusterType;
@@ -113,6 +114,7 @@ public class MongoClientSettingsFactoryBean extends AbstractFactoryBean<MongoCli
 	// encryption and retry
 
 	private @Nullable AutoEncryptionSettings autoEncryptionSettings;
+	private @Nullable ServerApi serverApi;
 
 	/**
 	 * @param socketConnectTimeoutMS in msec
@@ -395,6 +397,15 @@ public class MongoClientSettingsFactoryBean extends AbstractFactoryBean<MongoCli
 		this.autoEncryptionSettings = autoEncryptionSettings;
 	}
 
+	/**
+	 * @param serverApi can be {@literal null}.
+	 * @see MongoClientSettings.Builder#serverApi(ServerApi)
+	 * @since 3.3
+	 */
+	public void setServerApi(@Nullable ServerApi serverApi) {
+		this.serverApi = serverApi;
+	}
+
 	@Override
 	public Class<?> getObjectType() {
 		return MongoClientSettings.class;
@@ -476,9 +487,11 @@ public class MongoClientSettingsFactoryBean extends AbstractFactoryBean<MongoCli
 		if (retryWrites != null) {
 			builder = builder.retryWrites(retryWrites);
 		}
-
 		if (uUidRepresentation != null) {
-			builder.uuidRepresentation(uUidRepresentation);
+			builder = builder.uuidRepresentation(uUidRepresentation);
+		}
+		if (serverApi != null) {
+			builder = builder.serverApi(serverApi);
 		}
 
 		return builder.build();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDatabaseFactorySupport.java

@@ -84,18 +84,10 @@ public abstract class MongoDatabaseFactorySupport<C> implements MongoDatabaseFac
 		this.writeConcern = writeConcern;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase()
-	 */
 	public MongoDatabase getMongoDatabase() throws DataAccessException {
 		return getMongoDatabase(getDefaultDatabaseName());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase(java.lang.String)
-	 */
 	@Override
 	public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
 
@@ -118,28 +110,16 @@ public abstract class MongoDatabaseFactorySupport<C> implements MongoDatabaseFac
 	 */
 	protected abstract MongoDatabase doGetMongoDatabase(String dbName);
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.DisposableBean#destroy()
-	 */
 	public void destroy() throws Exception {
 		if (mongoInstanceCreated) {
 			closeClient();
 		}
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
-	 */
 	public PersistenceExceptionTranslator getExceptionTranslator() {
 		return this.exceptionTranslator;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.Session)
-	 */
 	public MongoDatabaseFactory withSession(ClientSession session) {
 		return new MongoDatabaseFactorySupport.ClientSessionBoundMongoDbFactory(session, this);
 	}
@@ -180,55 +160,31 @@ public abstract class MongoDatabaseFactorySupport<C> implements MongoDatabaseFac
 			this.delegate = delegate;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase()
-		 */
 		@Override
 		public MongoDatabase getMongoDatabase() throws DataAccessException {
 			return proxyMongoDatabase(delegate.getMongoDatabase());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase(java.lang.String)
-		 */
 		@Override
 		public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
 			return proxyMongoDatabase(delegate.getMongoDatabase(dbName));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
-		 */
 		@Override
 		public PersistenceExceptionTranslator getExceptionTranslator() {
 			return delegate.getExceptionTranslator();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
-		 */
 		@Override
 		public ClientSession getSession(ClientSessionOptions options) {
 			return delegate.getSession(options);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.ClientSession)
-		 */
 		@Override
 		public MongoDatabaseFactory withSession(ClientSession session) {
 			return delegate.withSession(session);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#isTransactionActive()
-		 */
 		@Override
 		public boolean isTransactionActive() {
 			return session != null && session.hasActiveTransaction();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDbFactorySupport.java

@@ -1,50 +0,0 @@
-/*
- * Copyright 2018-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.data.mongodb.core;
-
-import org.springframework.dao.support.PersistenceExceptionTranslator;
-
-/**
- * Common base class for usage with both {@link com.mongodb.client.MongoClients} defining common properties such as
- * database name and exception translator.
- * <br />
- * Not intended to be used directly.
- *
- * @author Christoph Strobl
- * @author Mark Paluch
- * @param <C> Client type.
- * @since 2.1
- * @see SimpleMongoClientDatabaseFactory
- * @deprecated since 3.0, use {@link MongoDatabaseFactorySupport} instead.
- */
-@Deprecated
-public abstract class MongoDbFactorySupport<C> extends MongoDatabaseFactorySupport<C> {
-
-	/**
-	 * Create a new {@link MongoDbFactorySupport} object given {@code mongoClient}, {@code databaseName},
-	 * {@code mongoInstanceCreated} and {@link PersistenceExceptionTranslator}.
-	 *
-	 * @param mongoClient must not be {@literal null}.
-	 * @param databaseName must not be {@literal null} or empty.
-	 * @param mongoInstanceCreated {@literal true} if the client instance was created by a subclass of
-	 *          {@link MongoDbFactorySupport} to close the client on {@link #destroy()}.
-	 * @param exceptionTranslator must not be {@literal null}.
-	 */
-	protected MongoDbFactorySupport(C mongoClient, String databaseName, boolean mongoInstanceCreated,
-			PersistenceExceptionTranslator exceptionTranslator) {
-		super(mongoClient, databaseName, mongoInstanceCreated, exceptionTranslator);
-	}
-}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoEncryptionSettingsFactoryBean.java

@@ -88,10 +88,6 @@ public class MongoEncryptionSettingsFactoryBean implements FactoryBean<AutoEncry
 		this.schemaMap = schemaMap;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see  org.springframework.beans.factory.FactoryBean#getObject()
-	 */
 	@Override
 	public AutoEncryptionSettings getObject() {
 
@@ -109,10 +105,6 @@ public class MongoEncryptionSettingsFactoryBean implements FactoryBean<AutoEncry
 		return source != null ? source : Collections.emptyMap();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see  org.springframework.beans.factory.FactoryBean#getObjectType()
-	 */
 	@Override
 	public Class<?> getObjectType() {
 		return AutoEncryptionSettings.class;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoExceptionTranslator.java

@@ -68,10 +68,6 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 	private static final Set<String> DATA_INTEGRITY_EXCEPTIONS = new HashSet<>(
 			Arrays.asList("WriteConcernException", "MongoWriteException", "MongoBulkWriteException"));
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.dao.support.PersistenceExceptionTranslator#translateExceptionIfPossible(java.lang.RuntimeException)
-	 */
 	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoJsonSchemaCreator.java

@@ -15,7 +15,24 @@
  */
 package org.springframework.data.mongodb.core;
 
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.function.Predicate;
+
+import org.springframework.data.mapping.PersistentProperty;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
+import org.springframework.data.mongodb.core.convert.NoOpDbRefResolver;
+import org.springframework.data.mongodb.core.mapping.Encrypted;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.mapping.MongoSimpleTypes;
+import org.springframework.data.mongodb.core.mapping.Unwrapped.Nullable;
+import org.springframework.data.mongodb.core.schema.JsonSchemaProperty;
 import org.springframework.data.mongodb.core.schema.MongoJsonSchema;
 import org.springframework.util.Assert;
 
@@ -46,6 +63,7 @@ import org.springframework.util.Assert;
  * {@link org.springframework.data.annotation.Id _id} properties using types that can be converted into
  * {@link org.bson.types.ObjectId} like {@link String} will be mapped to {@code type : 'object'} unless there is more
  * specific information available via the {@link org.springframework.data.mongodb.core.mapping.MongoId} annotation.
+ * {@link Encrypted} properties will contain {@literal encrypt} information.
  *
  * @author Christoph Strobl
  * @since 2.2
@@ -60,6 +78,111 @@ public interface MongoJsonSchemaCreator {
 	 */
 	MongoJsonSchema createSchemaFor(Class<?> type);
 
+	/**
+	 * Create a merged {@link MongoJsonSchema} out of the individual schemas of the given types by merging their
+	 * properties into one large {@link MongoJsonSchema schema}.
+	 *
+	 * @param types must not be {@literal null} nor contain {@literal null}.
+	 * @return new instance of {@link MongoJsonSchema}.
+	 * @since 3.4
+	 */
+	default MongoJsonSchema mergedSchemaFor(Class<?>... types) {
+
+		MongoJsonSchema[] schemas = Arrays.stream(types).map(this::createSchemaFor).toArray(MongoJsonSchema[]::new);
+		return MongoJsonSchema.merge(schemas);
+	}
+
+	/**
+	 * Filter matching {@link JsonSchemaProperty properties}.
+	 *
+	 * @param filter the {@link Predicate} to evaluate for inclusion. Must not be {@literal null}.
+	 * @return new instance of {@link MongoJsonSchemaCreator}.
+	 * @since 3.3
+	 */
+	MongoJsonSchemaCreator filter(Predicate<JsonSchemaPropertyContext> filter);
+
+	/**
+	 * Entry point to specify additional behavior for a given path.
+	 *
+	 * @param path the path using {@literal dot '.'} notation.
+	 * @return new instance of {@link PropertySpecifier}.
+	 * @since 3.4
+	 */
+	PropertySpecifier property(String path);
+
+	/**
+	 * The context in which a specific {@link #getProperty()} is encountered during schema creation.
+	 *
+	 * @since 3.3
+	 */
+	interface JsonSchemaPropertyContext {
+
+		/**
+		 * The path to a given field/property in dot notation.
+		 *
+		 * @return never {@literal null}.
+		 */
+		String getPath();
+
+		/**
+		 * The current property.
+		 *
+		 * @return never {@literal null}.
+		 */
+		MongoPersistentProperty getProperty();
+
+		/**
+		 * Obtain the {@link MongoPersistentEntity} for a given property.
+		 *
+		 * @param property must not be {@literal null}.
+		 * @param <T>
+		 * @return {@literal null} if the property is not an entity. It is nevertheless recommend to check
+		 *         {@link PersistentProperty#isEntity()} first.
+		 */
+		@Nullable
+		<T> MongoPersistentEntity<T> resolveEntity(MongoPersistentProperty property);
+
+	}
+
+	/**
+	 * A filter {@link Predicate} that matches {@link Encrypted encrypted properties} and those having nested ones.
+	 *
+	 * @return new instance of {@link Predicate}.
+	 * @since 3.3
+	 */
+	static Predicate<JsonSchemaPropertyContext> encryptedOnly() {
+
+		return new Predicate<JsonSchemaPropertyContext>() {
+
+			// cycle guard
+			private final Set<MongoPersistentProperty> seen = new HashSet<>();
+
+			@Override
+			public boolean test(JsonSchemaPropertyContext context) {
+				return extracted(context.getProperty(), context);
+			}
+
+			private boolean extracted(MongoPersistentProperty property, JsonSchemaPropertyContext context) {
+				if (property.isAnnotationPresent(Encrypted.class)) {
+					return true;
+				}
+
+				if (!property.isEntity() || seen.contains(property)) {
+					return false;
+				}
+
+				seen.add(property);
+
+				for (MongoPersistentProperty nested : context.resolveEntity(property)) {
+					if (extracted(nested, context)) {
+						return true;
+					}
+				}
+				return false;
+			}
+		};
+	}
+
 	/**
 	 * Creates a new {@link MongoJsonSchemaCreator} that is aware of conversions applied by the given
 	 * {@link MongoConverter}.
@@ -72,4 +195,56 @@ public interface MongoJsonSchemaCreator {
 		Assert.notNull(mongoConverter, "MongoConverter must not be null!");
 		return new MappingMongoJsonSchemaCreator(mongoConverter);
 	}
+
+	/**
+	 * Creates a new {@link MongoJsonSchemaCreator} that is aware of type mappings and potential
+	 * {@link org.springframework.data.spel.spi.EvaluationContextExtension extensions}.
+	 *
+	 * @param mappingContext must not be {@literal null}.
+	 * @return new instance of {@link MongoJsonSchemaCreator}.
+	 * @since 3.3
+	 */
+	static MongoJsonSchemaCreator create(MappingContext mappingContext) {
+
+		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, mappingContext);
+		converter.setCustomConversions(MongoCustomConversions.create(config -> {}));
+		converter.afterPropertiesSet();
+
+		return create(converter);
+	}
+
+	/**
+	 * Creates a new {@link MongoJsonSchemaCreator} that does not consider potential extensions - suitable for testing. We
+	 * recommend to use {@link #create(MappingContext)}.
+	 *
+	 * @return new instance of {@link MongoJsonSchemaCreator}.
+	 * @since 3.3
+	 */
+	static MongoJsonSchemaCreator create() {
+
+		MongoMappingContext mappingContext = new MongoMappingContext();
+		mappingContext.setSimpleTypeHolder(MongoSimpleTypes.HOLDER);
+		mappingContext.afterPropertiesSet();
+
+		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, mappingContext);
+		converter.setCustomConversions(MongoCustomConversions.create(config -> {}));
+		converter.afterPropertiesSet();
+
+		return create(converter);
+	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 3.4
+	 */
+	interface PropertySpecifier {
+
+		/**
+		 * Set additional type parameters for polymorphic ones.
+		 *
+		 * @param types must not be {@literal null}.
+		 * @return the source
+		 */
+		MongoJsonSchemaCreator withTypes(Class<?>... types);
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoOperations.java

@@ -20,6 +20,7 @@ import java.util.List;
 import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
+import java.util.stream.Stream;
 
 import org.bson.Document;
 import org.springframework.data.geo.GeoResults;
@@ -32,8 +33,6 @@ import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
 import org.springframework.data.mongodb.core.index.IndexOperations;
-import org.springframework.data.mongodb.core.mapreduce.GroupBy;
-import org.springframework.data.mongodb.core.mapreduce.GroupByResults;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceResults;
 import org.springframework.data.mongodb.core.query.BasicQuery;
@@ -42,7 +41,6 @@ import org.springframework.data.mongodb.core.query.NearQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
-import org.springframework.data.util.CloseableIterator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -57,8 +55,7 @@ import com.mongodb.client.result.UpdateResult;
 /**
  * Interface that specifies a basic set of MongoDB operations. Implemented by {@link MongoTemplate}. Not often used but
  * a useful option for extensibility and testability (as it can be easily mocked, stubbed, or be the target of a JDK
- * proxy).
- * <br />
+ * proxy). <br />
  * <strong>NOTE:</strong> Some operations cannot be executed within a MongoDB transaction. Please refer to the MongoDB
  * specific documentation to learn more about <a href="https://docs.mongodb.com/manual/core/transactions/">Multi
  * Document Transactions</a>.
@@ -84,7 +81,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	String getCollectionName(Class<?> entityClass);
 
 	/**
-	 * Execute the a MongoDB command expressed as a JSON string. Parsing is delegated to {@link Document#parse(String)} to
+	 * Execute a MongoDB command expressed as a JSON string. Parsing is delegated to {@link Document#parse(String)} to
 	 * obtain the {@link Document} holding the actual command. Any errors that result from executing this command will be
 	 * converted into Spring's DAO exception hierarchy.
 	 *
@@ -124,8 +121,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	void executeQuery(Query query, String collectionName, DocumentCallbackHandler dch);
 
 	/**
-	 * Executes a {@link DbCallback} translating any exceptions as necessary.
-	 * <br />
+	 * Executes a {@link DbCallback} translating any exceptions as necessary. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param action callback object that specifies the MongoDB actions to perform on the passed in DB instance. Must not
@@ -137,8 +133,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> T execute(DbCallback<T> action);
 
 	/**
-	 * Executes the given {@link CollectionCallback} on the entity collection of the specified class.
-	 * <br />
+	 * Executes the given {@link CollectionCallback} on the entity collection of the specified class. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
@@ -150,8 +145,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> T execute(Class<?> entityClass, CollectionCallback<T> action);
 
 	/**
-	 * Executes the given {@link CollectionCallback} on the collection of the given name.
-	 * <br />
+	 * Executes the given {@link CollectionCallback} on the collection of the given name. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param collectionName the name of the collection that specifies which {@link MongoCollection} instance will be
@@ -175,8 +169,7 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Obtain a {@link ClientSession session} bound instance of {@link SessionScoped} binding the {@link ClientSession}
-	 * provided by the given {@link Supplier} to each and every command issued against MongoDB.
-	 * <br />
+	 * provided by the given {@link Supplier} to each and every command issued against MongoDB. <br />
 	 * <strong>Note:</strong> It is up to the caller to manage the {@link ClientSession} lifecycle. Use the
 	 * {@link SessionScoped#execute(SessionCallback, Consumer)} hook to potentially close the {@link ClientSession}.
 	 *
@@ -211,8 +204,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	}
 
 	/**
-	 * Obtain a {@link ClientSession} bound instance of {@link MongoOperations}.
-	 * <br />
+	 * Obtain a {@link ClientSession} bound instance of {@link MongoOperations}. <br />
 	 * <strong>Note:</strong> It is up to the caller to manage the {@link ClientSession} lifecycle.
 	 *
 	 * @param session must not be {@literal null}.
@@ -225,34 +217,34 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * Executes the given {@link Query} on the entity collection of the specified {@code entityType} backed by a Mongo DB
 	 * {@link com.mongodb.client.FindIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to
-	 * be closed.
+	 * Returns a {@link String} that wraps the Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
 	 *
 	 * @param query the query class that specifies the criteria used to find a record and also an optional fields
 	 *          specification. Must not be {@literal null}.
 	 * @param entityType must not be {@literal null}.
 	 * @param <T> element return type
-	 * @return will never be {@literal null}.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 1.7
 	 */
-	<T> CloseableIterator<T> stream(Query query, Class<T> entityType);
+	<T> Stream<T> stream(Query query, Class<T> entityType);
 
 	/**
 	 * Executes the given {@link Query} on the entity collection of the specified {@code entityType} and collection backed
 	 * by a Mongo DB {@link com.mongodb.client.FindIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to
-	 * be closed.
+	 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
 	 *
 	 * @param query the query class that specifies the criteria used to find a record and also an optional fields
 	 *          specification. Must not be {@literal null}.
 	 * @param entityType must not be {@literal null}.
 	 * @param collectionName must not be {@literal null} or empty.
 	 * @param <T> element return type
-	 * @return will never be {@literal null}.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 1.10
 	 */
-	<T> CloseableIterator<T> stream(Query query, Class<T> entityType, String collectionName);
+	<T> Stream<T> stream(Query query, Class<T> entityType, String collectionName);
 
 	/**
 	 * Create an uncapped collection with a name based on the provided entity class.
@@ -299,8 +291,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * Get a {@link MongoCollection} by its name. The returned collection may not exists yet (except in local memory) and
 	 * is created on first interaction with the server. Collections can be explicitly created via
 	 * {@link #createCollection(Class)}. Please make sure to check if the collection {@link #collectionExists(Class)
-	 * exists} first.
-	 * <br />
+	 * exists} first. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection. Must not be {@literal null}.
@@ -309,8 +300,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	MongoCollection<Document> getCollection(String collectionName);
 
 	/**
-	 * Check to see if a collection with a name indicated by the entity class exists.
-	 * <br />
+	 * Check to see if a collection with a name indicated by the entity class exists. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param entityClass class that determines the name of the collection. Must not be {@literal null}.
@@ -319,8 +309,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> boolean collectionExists(Class<T> entityClass);
 
 	/**
-	 * Check to see if a collection with a given name exists.
-	 * <br />
+	 * Check to see if a collection with a given name exists. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection. Must not be {@literal null}.
@@ -329,8 +318,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	boolean collectionExists(String collectionName);
 
 	/**
-	 * Drop the collection with the name indicated by the entity class.
-	 * <br />
+	 * Drop the collection with the name indicated by the entity class. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param entityClass class that determines the collection to drop/delete. Must not be {@literal null}.
@@ -338,8 +326,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> void dropCollection(Class<T> entityClass);
 
 	/**
-	 * Drop the collection with the given name.
-	 * <br />
+	 * Drop the collection with the given name. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection to drop/delete.
@@ -402,11 +389,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	BulkOperations bulkOps(BulkMode mode, @Nullable Class<?> entityType, String collectionName);
 
 	/**
-	 * Query for a list of objects of type T from the collection used by the entity class.
-	 * <br />
+	 * Query for a list of objects of type T from the collection used by the entity class. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
 	 *
@@ -416,11 +401,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> List<T> findAll(Class<T> entityClass);
 
 	/**
-	 * Query for a list of objects of type T from the specified collection.
-	 * <br />
+	 * Query for a list of objects of type T from the specified collection. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
 	 *
@@ -430,43 +413,6 @@ public interface MongoOperations extends FluentMongoOperations {
 	 */
 	<T> List<T> findAll(Class<T> entityClass, String collectionName);
 
-	/**
-	 * Execute a group operation over the entire collection. The group operation entity class should match the 'shape' of
-	 * the returned object that takes int account the initial document structure as well as any finalize functions.
-	 *
-	 * @param inputCollectionName the collection where the group operation will read from
-	 * @param groupBy the conditions under which the group operation will be performed, e.g. keys, initial document,
-	 *          reduce function.
-	 * @param entityClass The parametrized type of the returned list
-	 * @return The results of the group operation
-	 * @deprecated since 2.2. The {@code group} command has been removed in MongoDB Server 4.2.0. <br />
-	 *             Please use {@link #aggregate(TypedAggregation, String, Class) } with a
-	 *             {@link org.springframework.data.mongodb.core.aggregation.GroupOperation} instead.
-	 */
-	@Deprecated
-	<T> GroupByResults<T> group(String inputCollectionName, GroupBy groupBy, Class<T> entityClass);
-
-	/**
-	 * Execute a group operation restricting the rows to those which match the provided Criteria. The group operation
-	 * entity class should match the 'shape' of the returned object that takes int account the initial document structure
-	 * as well as any finalize functions.
-	 *
-	 * @param criteria The criteria that restricts the row that are considered for grouping. If not specified all rows are
-	 *          considered.
-	 * @param inputCollectionName the collection where the group operation will read from
-	 * @param groupBy the conditions under which the group operation will be performed, e.g. keys, initial document,
-	 *          reduce function.
-	 * @param entityClass The parametrized type of the returned list
-	 * @return The results of the group operation
-	 * @deprecated since 2.2. The {@code group} command has been removed in MongoDB Server 4.2.0. <br />
-	 *             Please use {@link #aggregate(TypedAggregation, String, Class) } with a
-	 *             {@link org.springframework.data.mongodb.core.aggregation.GroupOperation} and
-	 *             {@link org.springframework.data.mongodb.core.aggregation.MatchOperation} instead.
-	 */
-	@Deprecated
-	<T> GroupByResults<T> group(@Nullable Criteria criteria, String inputCollectionName, GroupBy groupBy,
-			Class<T> entityClass);
-
 	/**
 	 * Execute an aggregation operation. The raw results will be mapped to the given entity class. The name of the
 	 * inputCollection is derived from the inputType of the aggregation.
@@ -521,9 +467,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
-	 * needs to be closed. The raw results will be mapped to the given entity class. The name of the inputCollection is
-	 * derived from the inputType of the aggregation.
+	 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.AggregateIterable} that needs to be
+	 * closed. The raw results will be mapped to the given entity class. The name of the inputCollection is derived from
+	 * the inputType of the aggregation.
 	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -532,35 +478,37 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          {@literal null}.
 	 * @param collectionName The name of the input collection to use for the aggreation.
 	 * @param outputType The parametrized type of the returned list, must not be {@literal null}.
-	 * @return The results of the aggregation operation.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 2.0
 	 */
-	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
+	<O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <br />
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
-	 * needs to be closed. The raw results will be mapped to the given entity class and are returned as stream. The name
-	 * of the inputCollection is derived from the inputType of the aggregation.
-	 * <br />
+	 * <p>
+	 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.AggregateIterable} that needs to be
+	 * closed. The raw results will be mapped to the given entity class and are returned as stream. The name of the
+	 * inputCollection is derived from the inputType of the aggregation.
+	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
 	 *
 	 * @param aggregation The {@link TypedAggregation} specification holding the aggregation operations, must not be
 	 *          {@literal null}.
 	 * @param outputType The parametrized type of the returned list, must not be {@literal null}.
-	 * @return The results of the aggregation operation.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 2.0
 	 */
-	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType);
+	<O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <br />
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
-	 * needs to be closed. The raw results will be mapped to the given entity class.
-	 * <br />
+	 * <p>
+	 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.AggregateIterable} that needs to be
+	 * closed. The raw results will be mapped to the given entity class.
+	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
 	 *
@@ -569,17 +517,18 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param inputType the inputType where the aggregation operation will read from, must not be {@literal null} or
 	 *          empty.
 	 * @param outputType The parametrized type of the returned list, must not be {@literal null}.
-	 * @return The results of the aggregation operation.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 2.0
 	 */
-	<O> CloseableIterator<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
+	<O> Stream<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <br />
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
-	 * needs to be closed. The raw results will be mapped to the given entity class.
-	 * <br />
+	 * <p>
+	 * Returns a {@link Stream} that wraps the Mongo DB {@link com.mongodb.client.AggregateIterable} that needs to be
+	 * closed. The raw results will be mapped to the given entity class.
+	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
 	 *
@@ -588,10 +537,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param collectionName the collection where the aggregation operation will read from, must not be {@literal null} or
 	 *          empty.
 	 * @param outputType The parametrized type of the returned list, must not be {@literal null}.
-	 * @return The results of the aggregation operation.
+	 * @return the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
+	 *         through a try-with-resources clause).
 	 * @since 2.0
 	 */
-	<O> CloseableIterator<O> aggregateStream(Aggregation aggregation, String collectionName, Class<O> outputType);
+	<O> Stream<O> aggregateStream(Aggregation aggregation, String collectionName, Class<O> outputType);
 
 	/**
 	 * Execute a map-reduce operation. The map-reduce operation will be formed with an output type of INLINE
@@ -601,7 +551,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param reduceFunction The JavaScript reduce function
 	 * @param entityClass The parametrized type of the returned list. Must not be {@literal null}.
 	 * @return The results of the map reduce operation
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> MapReduceResults<T> mapReduce(String inputCollectionName, String mapFunction, String reduceFunction,
 			Class<T> entityClass);
 
@@ -614,7 +566,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param mapReduceOptions Options that specify detailed map-reduce behavior.
 	 * @param entityClass The parametrized type of the returned list. Must not be {@literal null}.
 	 * @return The results of the map reduce operation
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> MapReduceResults<T> mapReduce(String inputCollectionName, String mapFunction, String reduceFunction,
 			@Nullable MapReduceOptions mapReduceOptions, Class<T> entityClass);
 
@@ -628,7 +582,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param reduceFunction The JavaScript reduce function
 	 * @param entityClass The parametrized type of the returned list. Must not be {@literal null}.
 	 * @return The results of the map reduce operation
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> MapReduceResults<T> mapReduce(Query query, String inputCollectionName, String mapFunction, String reduceFunction,
 			Class<T> entityClass);
 
@@ -642,7 +598,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param mapReduceOptions Options that specify detailed map-reduce behavior
 	 * @param entityClass The parametrized type of the returned list. Must not be {@literal null}.
 	 * @return The results of the map reduce operation
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> MapReduceResults<T> mapReduce(Query query, String inputCollectionName, String mapFunction, String reduceFunction,
 			@Nullable MapReduceOptions mapReduceOptions, Class<T> entityClass);
 
@@ -701,11 +659,9 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Map the results of an ad-hoc query on the collection for the entity class to a single instance of an object of the
-	 * specified type.
-	 * <br />
+	 * specified type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -719,11 +675,9 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Map the results of an ad-hoc query on the specified collection to a single instance of an object of the specified
-	 * type.
-	 * <br />
+	 * type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -767,11 +721,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	boolean exists(Query query, @Nullable Class<?> entityClass, String collectionName);
 
 	/**
-	 * Map the results of an ad-hoc query on the collection for the entity class to a List of the specified type.
-	 * <br />
+	 * Map the results of an ad-hoc query on the collection for the entity class to a List of the specified type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -783,11 +735,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> List<T> find(Query query, Class<T> entityClass);
 
 	/**
-	 * Map the results of an ad-hoc query on the specified collection to a List of the specified type.
-	 * <br />
+	 * Map the results of an ad-hoc query on the specified collection to a List of the specified type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -1119,10 +1069,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	/**
 	 * Map the results of an ad-hoc query on the collection for the entity type to a single instance of an object of the
 	 * specified type. The first document that matches the query is returned and also removed from the collection in the
-	 * database.
-	 * <br />
-	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}.
-	 * <br />
+	 * database. <br />
+	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -1139,8 +1087,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * type. The first document that matches the query is returned and also removed from the collection in the database.
 	 * <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -1159,18 +1106,17 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
-	 * This method uses an
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
 	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
-	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
-	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
-	 * {@link #estimatedCount(Class)} for empty queries instead.
+	 * aggregation execution} which may have an impact on performance.
 	 *
 	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
 	 *          {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the count of matching documents.
+	 * @see #exactCount(Query, Class)
+	 * @see #estimatedCount(Class)
 	 */
 	long count(Query query, Class<?> entityClass);
 
@@ -1181,25 +1127,44 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
-	 * This method uses an
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
 	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
-	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
-	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
-	 * {@link #estimatedCount(String)} for empty queries instead.
+	 * aggregation execution} which may have an impact on performance.
 	 *
 	 * @param query the {@link Query} class that specifies the criteria used to find documents.
 	 * @param collectionName must not be {@literal null} or empty.
 	 * @return the count of matching documents.
 	 * @see #count(Query, Class, String)
+	 * @see #exactCount(Query, String)
+	 * @see #estimatedCount(String)
 	 */
 	long count(Query query, String collectionName);
 
+	/**
+	 * Returns the number of documents for the given {@link Query} by querying the given collection using the given entity
+	 * class to map the given {@link Query}. <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
+	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} which may have an impact on performance.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
+	 *          {@literal null}.
+	 * @param entityClass the parametrized type. Can be {@literal null}.
+	 * @param collectionName must not be {@literal null} or empty.
+	 * @return the count of matching documents.
+	 * @see #count(Query, Class, String)
+	 * @see #estimatedCount(String)
+	 */
+	long count(Query query, @Nullable Class<?> entityClass, String collectionName);
+
 	/**
 	 * Estimate the number of documents, in the collection {@link #getCollectionName(Class) identified by the given type},
-	 * based on collection statistics.
-	 * <br />
+	 * based on collection statistics. <br />
 	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
 	 * transactions.
 	 *
@@ -1214,8 +1179,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	}
 
 	/**
-	 * Estimate the number of documents in the given collection based on collection statistics.
-	 * <br />
+	 * Estimate the number of documents in the given collection based on collection statistics. <br />
 	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
 	 * transactions.
 	 *
@@ -1225,14 +1189,60 @@ public interface MongoOperations extends FluentMongoOperations {
 	 */
 	long estimatedCount(String collectionName);
 
+	/**
+	 * Returns the number of documents for the given {@link Query} by querying the collection of the given entity class.
+	 * <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method uses an
+	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
+	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
+	 * {@link #estimatedCount(Class)} for empty queries instead.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
+	 *          {@literal null}.
+	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
+	 * @return the count of matching documents.
+	 * @since 3.4
+	 */
+	default long exactCount(Query query, Class<?> entityClass) {
+		return exactCount(query, entityClass, getCollectionName(entityClass));
+	}
+
+	/**
+	 * Returns the number of documents for the given {@link Query} querying the given collection. The given {@link Query}
+	 * must solely consist of document field references as we lack type information to map potential property references
+	 * onto document fields. Use {@link #count(Query, Class, String)} to get full type specific support. <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method uses an
+	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
+	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
+	 * {@link #estimatedCount(String)} for empty queries instead.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents.
+	 * @param collectionName must not be {@literal null} or empty.
+	 * @return the count of matching documents.
+	 * @see #count(Query, Class, String)
+	 * @since 3.4
+	 */
+	default long exactCount(Query query, String collectionName) {
+		return exactCount(query, null, collectionName);
+	}
+
 	/**
 	 * Returns the number of documents for the given {@link Query} by querying the given collection using the given entity
 	 * class to map the given {@link Query}. <br />
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
+	 * count all matches. <br />
 	 * This method uses an
 	 * {@link com.mongodb.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
 	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
@@ -1244,20 +1254,18 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param entityClass the parametrized type. Can be {@literal null}.
 	 * @param collectionName must not be {@literal null} or empty.
 	 * @return the count of matching documents.
+	 * @since 3.4
 	 */
-	long count(Query query, @Nullable Class<?> entityClass, String collectionName);
+	long exactCount(Query query, @Nullable Class<?> entityClass, String collectionName);
 
 	/**
-	 * Insert the object into the collection for the entity type of the object to save.
-	 * <br />
-	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}.
-	 * <br />
+	 * Insert the object into the collection for the entity type of the object to save. <br />
+	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
 	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
 	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation" > Spring's
-	 * Type Conversion"</a> for more details.
-	 * <br />
+	 * Type Conversion"</a> for more details. <br />
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 * <br />
 	 * The {@code objectToSave} must not be collection-like.
@@ -1269,11 +1277,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	<T> T insert(T objectToSave);
 
 	/**
-	 * Insert the object into the specified collection.
-	 * <br />
+	 * Insert the object into the specified collection. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 * <br />
 	 * The {@code objectToSave} must not be collection-like.
@@ -1314,17 +1320,14 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Save the object to the collection for the entity type of the object to save. This will perform an insert if the
-	 * object is not already present, that is an 'upsert'.
-	 * <br />
+	 * object is not already present, that is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
 	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
 	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation" > Spring's
-	 * Type Conversion"</a> for more details.
-	 * <br />
+	 * Type Conversion"</a> for more details. <br />
 	 * The {@code objectToSave} must not be collection-like.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
@@ -1335,16 +1338,14 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Save the object to the specified collection. This will perform an insert if the object is not already present, that
-	 * is an 'upsert'.
-	 * <br />
+	 * is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API.
-	 * See <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type Conversion</a> for more details.
-	 * <br />
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
+	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type
+	 * Conversion</a> for more details. <br />
 	 * The {@code objectToSave} must not be collection-like.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoServerApiFactoryBean.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2021-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.lang.Nullable;
+import org.springframework.util.ObjectUtils;
+
+import com.mongodb.ServerApi;
+import com.mongodb.ServerApi.Builder;
+import com.mongodb.ServerApiVersion;
+
+/**
+ * {@link FactoryBean} for creating {@link ServerApi} using the {@link ServerApi.Builder}.
+ *
+ * @author Christoph Strobl
+ * @since 3.3
+ */
+public class MongoServerApiFactoryBean implements FactoryBean<ServerApi> {
+
+	private String version;
+	private @Nullable Boolean deprecationErrors;
+	private @Nullable Boolean strict;
+
+	/**
+	 * @param version the version string either as the enum name or the server version value.
+	 * @see ServerApiVersion
+	 */
+	public void setVersion(String version) {
+		this.version = version;
+	}
+
+	/**
+	 * @param deprecationErrors
+	 * @see ServerApi.Builder#deprecationErrors(boolean)
+	 */
+	public void setDeprecationErrors(@Nullable Boolean deprecationErrors) {
+		this.deprecationErrors = deprecationErrors;
+	}
+
+	/**
+	 * @param strict
+	 * @see ServerApi.Builder#strict(boolean)
+	 */
+	public void setStrict(@Nullable Boolean strict) {
+		this.strict = strict;
+	}
+
+	@Nullable
+	@Override
+	public ServerApi getObject() throws Exception {
+
+		Builder builder = ServerApi.builder().version(version());
+
+		if (deprecationErrors != null) {
+			builder = builder.deprecationErrors(deprecationErrors);
+		}
+		if (strict != null) {
+			builder = builder.strict(strict);
+		}
+		return builder.build();
+	}
+
+	@Nullable
+	@Override
+	public Class<?> getObjectType() {
+		return ServerApi.class;
+	}
+
+	private ServerApiVersion version() {
+		try {
+			// lookup by name eg. 'V1'
+			return ObjectUtils.caseInsensitiveValueOf(ServerApiVersion.values(), version);
+		} catch (IllegalArgumentException e) {
+			// or just the version number, eg. just '1'
+			return ServerApiVersion.findByValue(version);
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/PropertyOperations.java

@@ -16,18 +16,19 @@
 package org.springframework.data.mongodb.core;
 
 import org.bson.Document;
-import org.springframework.data.mapping.SimplePropertyHandler;
+
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
-import org.springframework.data.projection.ProjectionFactory;
-import org.springframework.data.projection.ProjectionInformation;
-import org.springframework.util.ClassUtils;
+import org.springframework.data.mongodb.core.mapping.PersistentPropertyTranslator;
+import org.springframework.data.projection.EntityProjection;
+import org.springframework.data.util.Predicates;
 
 /**
  * Common operations performed on properties of an entity like extracting fields information for projection creation.
  *
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @since 2.1
  */
 class PropertyOperations {
@@ -40,37 +41,37 @@ class PropertyOperations {
 
 	/**
 	 * For cases where {@code fields} is {@link Document#isEmpty() empty} include only fields that are required for
-	 * creating the projection (target) type if the {@code targetType} is a {@literal DTO projection} or a
+	 * creating the projection (target) type if the {@code EntityProjection} is a {@literal DTO projection} or a
 	 * {@literal closed interface projection}.
 	 *
-	 * @param projectionFactory must not be {@literal null}.
+	 * @param projection must not be {@literal null}.
 	 * @param fields must not be {@literal null}.
-	 * @param domainType must not be {@literal null}.
-	 * @param targetType must not be {@literal null}.
 	 * @return {@link Document} with fields to be included.
 	 */
-	Document computeFieldsForProjection(ProjectionFactory projectionFactory, Document fields, Class<?> domainType,
-			Class<?> targetType) {
+	Document computeMappedFieldsForProjection(EntityProjection<?, ?> projection,
+			Document fields) {
 
-		if (!fields.isEmpty() || ClassUtils.isAssignable(domainType, targetType)) {
+		if (!projection.isClosedProjection()) {
 			return fields;
 		}
 
 		Document projectedFields = new Document();
 
-		if (targetType.isInterface()) {
-
-			ProjectionInformation projectionInformation = projectionFactory.getProjectionInformation(targetType);
-
-			if (projectionInformation.isClosed()) {
-				projectionInformation.getInputProperties().forEach(it -> projectedFields.append(it.getName(), 1));
-			}
+		if (projection.getMappedType().getType().isInterface()) {
+			projection.forEach(it -> {
+				projectedFields.put(it.getPropertyPath().getSegment(), 1);
+			});
 		} else {
 
-			MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(targetType);
-			if (entity != null) {
-				entity.doWithProperties(
-						(SimplePropertyHandler) persistentProperty -> projectedFields.append(persistentProperty.getName(), 1));
+			// DTO projections use merged metadata between domain type and result type
+			PersistentPropertyTranslator translator = PersistentPropertyTranslator.create(
+					mappingContext.getRequiredPersistentEntity(projection.getDomainType()),
+					Predicates.negate(MongoPersistentProperty::hasExplicitFieldName));
+
+			MongoPersistentEntity<?> persistentEntity = mappingContext
+					.getRequiredPersistentEntity(projection.getMappedType());
+			for (MongoPersistentProperty property : persistentEntity) {
+				projectedFields.put(translator.translate(property).getFieldName(), 1);
 			}
 		}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/QueryOperations.java

@@ -28,6 +28,7 @@ import java.util.stream.Collectors;
 import org.bson.BsonValue;
 import org.bson.Document;
 import org.bson.codecs.Codec;
+
 import org.springframework.data.mapping.PropertyPath;
 import org.springframework.data.mapping.PropertyReferenceException;
 import org.springframework.data.mapping.context.MappingContext;
@@ -54,11 +55,10 @@ import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
 import org.springframework.data.mongodb.core.query.UpdateDefinition.ArrayFilter;
 import org.springframework.data.mongodb.util.BsonUtils;
-import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.EntityProjection;
 import org.springframework.data.util.Lazy;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
 import com.mongodb.client.model.CountOptions;
@@ -288,45 +288,59 @@ class QueryOperations {
 			return queryMapper.getMappedObject(getQueryObject(), entity);
 		}
 
-		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType,
-				ProjectionFactory projectionFactory) {
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity,
+				EntityProjection<?, ?> projection) {
 
-			Document fields = new Document();
+			Document fields = evaluateFields(entity);
 
-			for (Entry<String, Object> entry : query.getFieldsObject().entrySet()) {
+			if (entity == null) {
+				return fields;
+			}
+
+			Document mappedFields;
+			if (!fields.isEmpty()) {
+				mappedFields = queryMapper.getMappedFields(fields, entity);
+			} else {
+				mappedFields = propertyOperations.computeMappedFieldsForProjection(projection, fields);
+				mappedFields = queryMapper.addMetaAttributes(mappedFields, entity);
+			}
+
+			if (entity.hasTextScoreProperty() && mappedFields.containsKey(entity.getTextScoreProperty().getFieldName())
+					&& !query.getQueryObject().containsKey("$text")) {
+				mappedFields.remove(entity.getTextScoreProperty().getFieldName());
+			}
+
+			if (mappedFields.isEmpty()) {
+				return BsonUtils.EMPTY_DOCUMENT;
+			}
+
+			return mappedFields;
+		}
+
+		private Document evaluateFields(@Nullable MongoPersistentEntity<?> entity) {
+
+			Document fields = query.getFieldsObject();
+
+			if (fields.isEmpty()) {
+				return BsonUtils.EMPTY_DOCUMENT;
+			}
+
+			Document evaluated = new Document();
+
+			for (Entry<String, Object> entry : fields.entrySet()) {
 
 				if (entry.getValue() instanceof MongoExpression) {
 
 					AggregationOperationContext ctx = entity == null ? Aggregation.DEFAULT_CONTEXT
 							: new RelaxedTypeBasedAggregationOperationContext(entity.getType(), mappingContext, queryMapper);
 
-					fields.put(entry.getKey(), AggregationExpression.from((MongoExpression) entry.getValue()).toDocument(ctx));
+					evaluated.put(entry.getKey(), AggregationExpression.from((MongoExpression) entry.getValue()).toDocument(ctx));
 				} else {
-					fields.put(entry.getKey(), entry.getValue());
+					evaluated.put(entry.getKey(), entry.getValue());
 				}
 			}
 
-			Document mappedFields = fields;
-
-			if (entity == null) {
-				return mappedFields;
-			}
-
-			Document projectedFields = propertyOperations.computeFieldsForProjection(projectionFactory, fields,
-					entity.getType(), targetType);
-
-			if (ObjectUtils.nullSafeEquals(fields, projectedFields)) {
-				mappedFields = queryMapper.getMappedFields(projectedFields, entity);
-			} else {
-				mappedFields = queryMapper.getMappedFields(projectedFields,
-						mappingContext.getRequiredPersistentEntity(targetType));
-			}
-
-			if (entity.hasTextScoreProperty() && !query.getQueryObject().containsKey("$text")) {
-				mappedFields.remove(entity.getTextScoreProperty().getFieldName());
-			}
-
-			return mappedFields;
+			return evaluated;
 		}
 
 		/**
@@ -388,8 +402,8 @@ class QueryOperations {
 		}
 
 		@Override
-		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType,
-				ProjectionFactory projectionFactory) {
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity,
+				EntityProjection<?, ?> projection) {
 			return getMappedFields(entity);
 		}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveAggregationOperationSupport.java

@@ -46,10 +46,6 @@ class ReactiveAggregationOperationSupport implements ReactiveAggregationOperatio
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation#aggregateAndReturn(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveAggregation<T> aggregateAndReturn(Class<T> domainType) {
 
@@ -75,10 +71,6 @@ class ReactiveAggregationOperationSupport implements ReactiveAggregationOperatio
 			this.collection = collection;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.AggregationOperationWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public AggregationOperationWithAggregation<T> inCollection(String collection) {
 
@@ -87,10 +79,6 @@ class ReactiveAggregationOperationSupport implements ReactiveAggregationOperatio
 			return new ReactiveAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.AggregationOperationWithAggregation#by(org.springframework.data.mongodb.core.Aggregation)
-		 */
 		@Override
 		public TerminatingAggregationOperation<T> by(Aggregation aggregation) {
 
@@ -99,10 +87,6 @@ class ReactiveAggregationOperationSupport implements ReactiveAggregationOperatio
 			return new ReactiveAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.TerminatingAggregationOperation#all()
-		 */
 		@Override
 		public Flux<T> all() {
 			return template.aggregate(aggregation, getCollectionName(aggregation), domainType);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveChangeStreamOperationSupport.java

@@ -46,10 +46,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation#changeStream(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveChangeStream<T> changeStream(Class<T> domainType) {
 
@@ -76,10 +72,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			this.options = options;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithCollection#watchCollection(java.lang.String)
-		 */
 		@Override
 		public ChangeStreamWithFilterAndProjection<T> watchCollection(String collection) {
 
@@ -88,10 +80,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return new ReactiveChangeStreamSupport<>(template, domainType, returnType, collection, options);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithCollection#watchCollection(java.lang.Class)
-		 */
 		@Override
 		public ChangeStreamWithFilterAndProjection<T> watchCollection(Class<?> entityClass) {
 
@@ -100,10 +88,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return watchCollection(template.getCollectionName(entityClass));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ResumingChangeStream#resumeAt(java.lang.Object)
-		 */
 		@Override
 		public TerminatingChangeStream<T> resumeAt(Object token) {
 
@@ -117,10 +101,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			});
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ResumingChangeStream#resumeAfter(java.lang.Object)
-		 */
 		@Override
 		public TerminatingChangeStream<T> resumeAfter(Object token) {
 
@@ -129,10 +109,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return withOptions(builder -> builder.resumeAfter((BsonValue) token));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ResumingChangeStream#startAfter(java.lang.Object)
-		 */
 		@Override
 		public TerminatingChangeStream<T> startAfter(Object token) {
 
@@ -141,10 +117,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return withOptions(builder -> builder.startAfter((BsonValue) token));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithOptions#withOptions(java.util.function.Consumer)
-		 */
 		@Override
 		public ReactiveChangeStreamSupport<T> withOptions(Consumer<ChangeStreamOptionsBuilder> optionsConsumer) {
 
@@ -154,10 +126,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return new ReactiveChangeStreamSupport<>(template, domainType, returnType, collection, builder.build());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithProjection#as(java.lang.Class)
-		 */
 		@Override
 		public <R> ChangeStreamWithFilterAndProjection<R> as(Class<R> resultType) {
 
@@ -166,19 +134,11 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return new ReactiveChangeStreamSupport<>(template, domainType, resultType, collection, options);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithFilter#filter(org.springframework.data.mongodb.core.aggregation.Aggregation)
-		 */
 		@Override
 		public ChangeStreamWithFilterAndProjection<T> filter(Aggregation filter) {
 			return withOptions(builder -> builder.filter(filter));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.ChangeStreamWithFilter#filter(org.springframework.data.mongodb.core.query.CriteriaDefinition)
-		 */
 		@Override
 		public ChangeStreamWithFilterAndProjection<T> filter(CriteriaDefinition by) {
 
@@ -188,10 +148,6 @@ class ReactiveChangeStreamOperationSupport implements ReactiveChangeStreamOperat
 			return filter(aggregation);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveChangeStreamOperation.TerminatingChangeStream#listen()
-		 */
 		@Override
 		public Flux<ChangeStreamEvent<T>> listen() {
 			return template.changeStream(collection, options != null ? options : ChangeStreamOptions.empty(), returnType);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFindOperationSupport.java

@@ -44,10 +44,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveFindOperation#query(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveFind<T> query(Class<T> domainType) {
 
@@ -81,10 +77,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			this.query = query;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.FindWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public FindWithProjection<T> inCollection(String collection) {
 
@@ -93,10 +85,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			return new ReactiveFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.FindWithProjection#as(java.lang.Class)
-		 */
 		@Override
 		public <T1> FindWithQuery<T1> as(Class<T1> returnType) {
 
@@ -105,10 +93,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			return new ReactiveFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.FindWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-		 */
 		@Override
 		public TerminatingFind<T> matching(Query query) {
 
@@ -117,10 +101,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			return new ReactiveFindSupport<>(template, domainType, returnType, collection, query);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#first()
-		 */
 		@Override
 		public Mono<T> first() {
 
@@ -130,10 +110,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			return result.next();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#one()
-		 */
 		@Override
 		public Mono<T> one() {
 
@@ -155,55 +131,31 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			});
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#all()
-		 */
 		@Override
 		public Flux<T> all() {
 			return doFind(null);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#tail()
-		 */
 		@Override
 		public Flux<T> tail() {
 			return doFind(template.new TailingQueryFindPublisherPreparer(query, domainType));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.FindWithQuery#near(org.springframework.data.mongodb.core.query.NearQuery)
-		 */
 		@Override
 		public TerminatingFindNear<T> near(NearQuery nearQuery) {
 			return () -> template.geoNear(nearQuery, domainType, getCollectionName(), returnType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#count()
-		 */
 		@Override
 		public Mono<Long> count() {
 			return template.count(query, domainType, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#exists()
-		 */
 		@Override
 		public Mono<Boolean> exists() {
 			return template.exists(query, domainType, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.FindDistinct#distinct(java.lang.String)
-		 */
 		@Override
 		public TerminatingDistinct<Object> distinct(String field) {
 
@@ -255,10 +207,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 				this.field = field;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.DistinctWithProjection#as(java.lang.Class)
-			 */
 			@Override
 			public <R> TerminatingDistinct<R> as(Class<R> resultType) {
 
@@ -267,10 +215,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 				return new DistinctOperationSupport<>((ReactiveFindSupport) delegate.as(resultType), field);
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.DistinctWithQuery#matching(org.springframework.data.mongodb.core.query.Query)
-			 */
 			@Override
 			@SuppressWarnings("unchecked")
 			public TerminatingDistinct<T> matching(Query query) {
@@ -280,10 +224,6 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 				return new DistinctOperationSupport<>((ReactiveFindSupport<T>) delegate.matching(query), field);
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core..ReactiveFindOperation.TerminatingDistinct#all()
-			 */
 			@Override
 			public Flux<T> all() {
 				return delegate.doFindDistinct(field);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveInsertOperationSupport.java

@@ -38,10 +38,6 @@ class ReactiveInsertOperationSupport implements ReactiveInsertOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveInsertOperation#insert(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveInsert<T> insert(Class<T> domainType) {
 
@@ -63,10 +59,6 @@ class ReactiveInsertOperationSupport implements ReactiveInsertOperation {
 			this.collection = collection;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveInsertOperation.TerminatingInsert#one(java.lang.Object)
-		 */
 		@Override
 		public Mono<T> one(T object) {
 
@@ -75,10 +67,6 @@ class ReactiveInsertOperationSupport implements ReactiveInsertOperation {
 			return template.insert(object, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveInsertOperation.TerminatingInsert#all(java.util.Collection)
-		 */
 		@Override
 		public Flux<T> all(Collection<? extends T> objects) {
 
@@ -87,10 +75,6 @@ class ReactiveInsertOperationSupport implements ReactiveInsertOperation {
 			return template.insert(objects, getCollectionName());
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveInsertOperation.InsertWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public ReactiveInsert<T> inCollection(String collection) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoOperations.java

@@ -42,7 +42,6 @@ import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
 import org.springframework.lang.Nullable;
-import org.springframework.transaction.reactive.TransactionalOperator;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
@@ -58,8 +57,7 @@ import com.mongodb.reactivestreams.client.MongoCollection;
  * <p>
  * Implemented by {@link ReactiveMongoTemplate}. Not often used but a useful option for extensibility and testability
  * (as it can be easily mocked, stubbed, or be the target of a JDK proxy). Command execution using
- * {@link ReactiveMongoOperations} is deferred until subscriber subscribes to the {@link Publisher}.
- * <br />
+ * {@link ReactiveMongoOperations} is deferred until subscriber subscribes to the {@link Publisher}. <br />
  * <strong>NOTE:</strong> Some operations cannot be executed within a MongoDB transaction. Please refer to the MongoDB
  * specific documentation to learn more about <a href="https://docs.mongodb.com/manual/core/transactions/">Multi
  * Document Transactions</a>.
@@ -91,7 +89,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	ReactiveIndexOperations indexOps(Class<?> entityClass);
 
 	/**
-	 * Execute the a MongoDB command expressed as a JSON string. This will call the method JSON.parse that is part of the
+	 * Execute a MongoDB command expressed as a JSON string. This will call the method JSON.parse that is part of the
 	 * MongoDB driver to convert the JSON string to a Document. Any errors that result from executing this command will be
 	 * converted into Spring's DAO exception hierarchy.
 	 *
@@ -120,8 +118,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	Mono<Document> executeCommand(Document command, @Nullable ReadPreference readPreference);
 
 	/**
-	 * Executes a {@link ReactiveDatabaseCallback} translating any exceptions as necessary.
-	 * <br />
+	 * Executes a {@link ReactiveDatabaseCallback} translating any exceptions as necessary. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param action callback object that specifies the MongoDB actions to perform on the passed in DB instance. Must not
@@ -132,8 +129,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Flux<T> execute(ReactiveDatabaseCallback<T> action);
 
 	/**
-	 * Executes the given {@link ReactiveCollectionCallback} on the entity collection of the specified class.
-	 * <br />
+	 * Executes the given {@link ReactiveCollectionCallback} on the entity collection of the specified class. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
@@ -144,8 +140,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Flux<T> execute(Class<?> entityClass, ReactiveCollectionCallback<T> action);
 
 	/**
-	 * Executes the given {@link ReactiveCollectionCallback} on the collection of the given name.
-	 * <br />
+	 * Executes the given {@link ReactiveCollectionCallback} on the collection of the given name. <br />
 	 * Allows for returning a result object, that is a domain object or a collection of domain objects.
 	 *
 	 * @param collectionName the name of the collection that specifies which {@link MongoCollection} instance will be
@@ -158,8 +153,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Obtain a {@link ClientSession session} bound instance of {@link SessionScoped} binding the {@link ClientSession}
-	 * provided by the given {@link Supplier} to each and every command issued against MongoDB.
-	 * <br />
+	 * provided by the given {@link Supplier} to each and every command issued against MongoDB. <br />
 	 * <strong>Note:</strong> It is up to the caller to manage the {@link ClientSession} lifecycle. Use
 	 * {@link ReactiveSessionScoped#execute(ReactiveSessionCallback, Consumer)} to provide a hook for processing the
 	 * {@link ClientSession} when done.
@@ -177,8 +171,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Obtain a {@link ClientSession session} bound instance of {@link SessionScoped} binding a new {@link ClientSession}
-	 * with given {@literal sessionOptions} to each and every command issued against MongoDB.
-	 * <br />
+	 * with given {@literal sessionOptions} to each and every command issued against MongoDB. <br />
 	 * <strong>Note:</strong> It is up to the caller to manage the {@link ClientSession} lifecycle. Use
 	 * {@link ReactiveSessionScoped#execute(ReactiveSessionCallback, Consumer)} to provide a hook for processing the
 	 * {@link ClientSession} when done.
@@ -204,48 +197,14 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	ReactiveSessionScoped withSession(Publisher<ClientSession> sessionProvider);
 
 	/**
-	 * Obtain a {@link ClientSession} bound instance of {@link ReactiveMongoOperations}.
-	 * <br />
+	 * Obtain a {@link ClientSession} bound instance of {@link ReactiveMongoOperations}. <br />
 	 * <strong>Note:</strong> It is up to the caller to manage the {@link ClientSession} lifecycle.
 	 *
-	 * @param session must not be {@literal null}.
 	 * @return {@link ClientSession} bound instance of {@link ReactiveMongoOperations}.
 	 * @since 2.1
 	 */
 	ReactiveMongoOperations withSession(ClientSession session);
 
-	/**
-	 * Initiate a new {@link ClientSession} and obtain a {@link ClientSession session} bound instance of
-	 * {@link ReactiveSessionScoped}. Starts the transaction and adds the {@link ClientSession} to each and every command
-	 * issued against MongoDB.
-	 * <br />
-	 * Each {@link ReactiveSessionScoped#execute(ReactiveSessionCallback) execution} initiates a new managed transaction
-	 * that is {@link ClientSession#commitTransaction() committed} on success. Transactions are
-	 * {@link ClientSession#abortTransaction() rolled back} upon errors.
-	 *
-	 * @return new instance of {@link ReactiveSessionScoped}. Never {@literal null}.
-	 * @deprecated since 2.2. Use {@code @Transactional} or {@link TransactionalOperator}.
-	 */
-	@Deprecated
-	ReactiveSessionScoped inTransaction();
-
-	/**
-	 * Obtain a {@link ClientSession session} bound instance of {@link ReactiveSessionScoped}, start the transaction and
-	 * bind the {@link ClientSession} provided by the given {@link Publisher} to each and every command issued against
-	 * MongoDB.
-	 * <br />
-	 * Each {@link ReactiveSessionScoped#execute(ReactiveSessionCallback) execution} initiates a new managed transaction
-	 * that is {@link ClientSession#commitTransaction() committed} on success. Transactions are
-	 * {@link ClientSession#abortTransaction() rolled back} upon errors.
-	 *
-	 * @param sessionProvider must not be {@literal null}.
-	 * @return new instance of {@link ReactiveSessionScoped}. Never {@literal null}.
-	 * @since 2.1
-	 * @deprecated since 2.2. Use {@code @Transactional} or {@link TransactionalOperator}.
-	 */
-	@Deprecated
-	ReactiveSessionScoped inTransaction(Publisher<ClientSession> sessionProvider);
-
 	/**
 	 * Create an uncapped collection with a name based on the provided entity class.
 	 *
@@ -292,8 +251,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Get a {@link MongoCollection} by name. The returned collection may not exists yet (except in local memory) and is
 	 * created on first interaction with the server. Collections can be explicitly created via
 	 * {@link #createCollection(Class)}. Please make sure to check if the collection {@link #collectionExists(Class)
-	 * exists} first.
-	 * <br />
+	 * exists} first. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection.
@@ -302,8 +260,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	Mono<MongoCollection<Document>> getCollection(String collectionName);
 
 	/**
-	 * Check to see if a collection with a name indicated by the entity class exists.
-	 * <br />
+	 * Check to see if a collection with a name indicated by the entity class exists. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param entityClass class that determines the name of the collection. Must not be {@literal null}.
@@ -312,8 +269,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Mono<Boolean> collectionExists(Class<T> entityClass);
 
 	/**
-	 * Check to see if a collection with a given name exists.
-	 * <br />
+	 * Check to see if a collection with a given name exists. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection. Must not be {@literal null}.
@@ -322,8 +278,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	Mono<Boolean> collectionExists(String collectionName);
 
 	/**
-	 * Drop the collection with the name indicated by the entity class.
-	 * <br />
+	 * Drop the collection with the name indicated by the entity class. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param entityClass class that determines the collection to drop/delete. Must not be {@literal null}.
@@ -331,8 +286,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Mono<Void> dropCollection(Class<T> entityClass);
 
 	/**
-	 * Drop the collection with the given name.
-	 * <br />
+	 * Drop the collection with the given name. <br />
 	 * Translate any exceptions as necessary.
 	 *
 	 * @param collectionName name of the collection to drop/delete.
@@ -340,11 +294,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	Mono<Void> dropCollection(String collectionName);
 
 	/**
-	 * Query for a {@link Flux} of objects of type T from the collection used by the entity class.
-	 * <br />
+	 * Query for a {@link Flux} of objects of type T from the collection used by the entity class. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
 	 *
@@ -354,11 +306,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Flux<T> findAll(Class<T> entityClass);
 
 	/**
-	 * Query for a {@link Flux} of objects of type T from the specified collection.
-	 * <br />
+	 * Query for a {@link Flux} of objects of type T from the specified collection. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
 	 *
@@ -370,11 +320,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Map the results of an ad-hoc query on the collection for the entity class to a single instance of an object of the
-	 * specified type.
-	 * <br />
+	 * specified type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -387,11 +335,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Map the results of an ad-hoc query on the specified collection to a single instance of an object of the specified
-	 * type.
-	 * <br />
+	 * type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -437,8 +383,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Map the results of an ad-hoc query on the collection for the entity class to a {@link Flux} of the specified type.
 	 * <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -450,11 +395,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Flux<T> find(Query query, Class<T> entityClass);
 
 	/**
-	 * Map the results of an ad-hoc query on the specified collection to a {@link Flux} of the specified type.
-	 * <br />
+	 * Map the results of an ad-hoc query on the specified collection to a {@link Flux} of the specified type. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -565,11 +508,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<O> Flux<O> aggregate(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation.
-	 * <br />
+	 * Execute an aggregation operation. <br />
 	 * The raw results will be mapped to the given entity class and are returned as stream. The name of the
-	 * inputCollection is derived from the {@link TypedAggregation#getInputType() aggregation input type}.
-	 * <br />
+	 * inputCollection is derived from the {@link TypedAggregation#getInputType() aggregation input type}. <br />
 	 * Aggregation streaming cannot be used with {@link AggregationOptions#isExplain() aggregation explain} nor with
 	 * {@link AggregationOptions#getCursorBatchSize()}. Enabling explanation mode or setting batch size cause
 	 * {@link IllegalArgumentException}.
@@ -583,11 +524,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<O> Flux<O> aggregate(TypedAggregation<?> aggregation, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation.
-	 * <br />
+	 * Execute an aggregation operation. <br />
 	 * The raw results will be mapped to the given {@code ouputType}. The name of the inputCollection is derived from the
-	 * {@code inputType}.
-	 * <br />
+	 * {@code inputType}. <br />
 	 * Aggregation streaming cannot be used with {@link AggregationOptions#isExplain() aggregation explain} nor with
 	 * {@link AggregationOptions#getCursorBatchSize()}. Enabling explanation mode or setting batch size cause
 	 * {@link IllegalArgumentException}.
@@ -603,10 +542,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<O> Flux<O> aggregate(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation.
-	 * <br />
-	 * The raw results will be mapped to the given entity class.
-	 * <br />
+	 * Execute an aggregation operation. <br />
+	 * The raw results will be mapped to the given entity class. <br />
 	 * Aggregation streaming cannot be used with {@link AggregationOptions#isExplain() aggregation explain} nor with
 	 * {@link AggregationOptions#getCursorBatchSize()}. Enabling explanation mode or setting batch size cause
 	 * {@link IllegalArgumentException}.
@@ -901,10 +838,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	/**
 	 * Map the results of an ad-hoc query on the collection for the entity type to a single instance of an object of the
 	 * specified type. The first document that matches the query is returned and also removed from the collection in the
-	 * database.
-	 * <br />
-	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}.
-	 * <br />
+	 * database. <br />
+	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -920,8 +855,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * type. The first document that matches the query is returned and also removed from the collection in the database.
 	 * <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -939,18 +873,17 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
-	 * This method uses an
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
 	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
-	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
-	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
-	 * {@link #estimatedCount(Class)} for empty queries instead.
+	 * aggregation execution} which may have an impact on performance.
 	 *
 	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
 	 *          {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the count of matching documents.
+	 * @see #exactCount(Query, Class)
+	 * @see #estimatedCount(Class)
 	 */
 	Mono<Long> count(Query query, Class<?> entityClass);
 
@@ -961,18 +894,17 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
-	 * This method uses an
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
 	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
-	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
-	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
-	 * {@link #estimatedCount(String)} for empty queries instead.
+	 * aggregation execution} which may have an impact on performance.
 	 *
 	 * @param query the {@link Query} class that specifies the criteria used to find documents.
 	 * @param collectionName must not be {@literal null} or empty.
 	 * @return the count of matching documents.
 	 * @see #count(Query, Class, String)
+	 * @see #estimatedCount(String)
+	 * @see #exactCount(Query, String)
 	 */
 	Mono<Long> count(Query query, String collectionName);
 
@@ -982,26 +914,24 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
 	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
 	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
-	 * count all matches.
-	 * <br />
-	 * This method uses an
+	 * count all matches. <br />
+	 * This method may choose to use {@link #estimatedCount(Class)} for empty queries instead of running an
 	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
-	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
-	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
-	 * {@link #estimatedCount(String)} for empty queries instead.
+	 * aggregation execution} which may have an impact on performance.
 	 *
 	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
 	 *          {@literal null}.
 	 * @param entityClass the parametrized type. Can be {@literal null}.
 	 * @param collectionName must not be {@literal null} or empty.
 	 * @return the count of matching documents.
+	 * @see #estimatedCount(String)
+	 * @see #exactCount(Query, Class, String)
 	 */
 	Mono<Long> count(Query query, @Nullable Class<?> entityClass, String collectionName);
 
 	/**
 	 * Estimate the number of documents, in the collection {@link #getCollectionName(Class) identified by the given type},
-	 * based on collection statistics.
-	 * <br />
+	 * based on collection statistics. <br />
 	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
 	 * transactions.
 	 *
@@ -1016,8 +946,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	}
 
 	/**
-	 * Estimate the number of documents in the given collection based on collection statistics.
-	 * <br />
+	 * Estimate the number of documents in the given collection based on collection statistics. <br />
 	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
 	 * transactions.
 	 *
@@ -1028,16 +957,82 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	Mono<Long> estimatedCount(String collectionName);
 
 	/**
-	 * Insert the object into the collection for the entity type of the object to save.
-	 * <br />
-	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}.
+	 * Returns the number of documents for the given {@link Query} by querying the collection of the given entity class.
 	 * <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method uses an
+	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
+	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
+	 * {@link #estimatedCount(Class)} for empty queries instead.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
+	 *          {@literal null}.
+	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
+	 * @return the count of matching documents.
+	 * @since 3.4
+	 */
+	default Mono<Long> exactCount(Query query, Class<?> entityClass) {
+		return exactCount(query, entityClass, getCollectionName(entityClass));
+	}
+
+	/**
+	 * Returns the number of documents for the given {@link Query} querying the given collection. The given {@link Query}
+	 * must solely consist of document field references as we lack type information to map potential property references
+	 * onto document fields. Use {@link #count(Query, Class, String)} to get full type specific support. <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method uses an
+	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
+	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
+	 * {@link #estimatedCount(String)} for empty queries instead.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents.
+	 * @param collectionName must not be {@literal null} or empty.
+	 * @return the count of matching documents.
+	 * @see #count(Query, Class, String)
+	 * @since 3.4
+	 */
+	default Mono<Long> exactCount(Query query, String collectionName) {
+		return exactCount(query, null, collectionName);
+	}
+
+	/**
+	 * Returns the number of documents for the given {@link Query} by querying the given collection using the given entity
+	 * class to map the given {@link Query}. <br />
+	 * <strong>NOTE:</strong> Query {@link Query#getSkip() offset} and {@link Query#getLimit() limit} can have direct
+	 * influence on the resulting number of documents found as those values are passed on to the server and potentially
+	 * limit the range and order within which the server performs the count operation. Use an {@literal unpaged} query to
+	 * count all matches. <br />
+	 * This method uses an
+	 * {@link com.mongodb.reactivestreams.client.MongoCollection#countDocuments(org.bson.conversions.Bson, com.mongodb.client.model.CountOptions)
+	 * aggregation execution} even for empty {@link Query queries} which may have an impact on performance, but guarantees
+	 * shard, session and transaction compliance. In case an inaccurate count satisfies the applications needs use
+	 * {@link #estimatedCount(String)} for empty queries instead.
+	 *
+	 * @param query the {@link Query} class that specifies the criteria used to find documents. Must not be
+	 *          {@literal null}.
+	 * @param entityClass the parametrized type. Can be {@literal null}.
+	 * @param collectionName must not be {@literal null} or empty.
+	 * @return the count of matching documents.
+	 * @since 3.4
+	 */
+	Mono<Long> exactCount(Query query, @Nullable Class<?> entityClass, String collectionName);
+
+	/**
+	 * Insert the object into the collection for the entity type of the object to save. <br />
+	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
 	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
 	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation" > Spring's
-	 * Type Conversion"</a> for more details.
-	 * <br />
+	 * Type Conversion"</a> for more details. <br />
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 * <br />
 	 * The {@code objectToSave} must not be collection-like.
@@ -1049,11 +1044,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Mono<T> insert(T objectToSave);
 
 	/**
-	 * Insert the object into the specified collection.
-	 * <br />
+	 * Insert the object into the specified collection. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 * <br />
 	 * The {@code objectToSave} must not be collection-like.
@@ -1093,16 +1086,13 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	<T> Flux<T> insertAll(Collection<? extends T> objectsToSave);
 
 	/**
-	 * Insert the object into the collection for the entity type of the object to save.
-	 * <br />
-	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}.
-	 * <br />
+	 * Insert the object into the collection for the entity type of the object to save. <br />
+	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
 	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
 	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation" > Spring's
-	 * Type Conversion"</a> for more details.
-	 * <br />
+	 * Type Conversion"</a> for more details. <br />
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
@@ -1139,17 +1129,14 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Save the object to the collection for the entity type of the object to save. This will perform an insert if the
-	 * object is not already present, that is an 'upsert'.
-	 * <br />
+	 * object is not already present, that is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
 	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
 	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation" > Spring's
-	 * Type Conversion"</a> for more details.
-	 * <br />
+	 * Type Conversion"</a> for more details. <br />
 	 * The {@code objectToSave} must not be collection-like.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
@@ -1160,15 +1147,14 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Save the object to the specified collection. This will perform an insert if the object is not already present, that
-	 * is an 'upsert'.
-	 * <br />
+	 * is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API.
-	 * See <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type Conversion</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
+	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type
+	 * Conversion</a> for more details.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
 	 * @param collectionName name of the collection to store the object in. Must not be {@literal null}.
@@ -1179,15 +1165,14 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Save the object to the collection for the entity type of the object to save. This will perform an insert if the
-	 * object is not already present, that is an 'upsert'.
-	 * <br />
+	 * object is not already present, that is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API.
-	 * See <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation"> Spring's Type Conversion</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
+	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation"> Spring's Type
+	 * Conversion</a> for more details.
 	 *
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
 	 * @return the saved object.
@@ -1196,15 +1181,14 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 
 	/**
 	 * Save the object to the specified collection. This will perform an insert if the object is not already present, that
-	 * is an 'upsert'.
-	 * <br />
+	 * is an 'upsert'. <br />
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * If your object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API.
-	 * See <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type Conversion</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See
+	 * <a href="https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#validation">Spring's Type
+	 * Conversion</a> for more details.
 	 *
 	 * @param objectToSave the object to store in the collReactiveMongoOperationsection. Must not be {@literal null}.
 	 * @param collectionName name of the collection to store the object in. Must not be {@literal null}.
@@ -1477,11 +1461,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Map the results of an ad-hoc query on the collection for the entity class to a stream of objects of the specified
 	 * type. The stream uses a {@link com.mongodb.CursorType#TailableAwait tailable} cursor that may be an infinite
 	 * stream. The stream will not be completed unless the {@link org.reactivestreams.Subscription} is
-	 * {@link Subscription#cancel() canceled}.
-	 * <br />
+	 * {@link Subscription#cancel() canceled}. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -1496,11 +1478,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Map the results of an ad-hoc query on the collection for the entity class to a stream of objects of the specified
 	 * type. The stream uses a {@link com.mongodb.CursorType#TailableAwait tailable} cursor that may be an infinite
 	 * stream. The stream will not be completed unless the {@link org.reactivestreams.Subscription} is
-	 * {@link Subscription#cancel() canceled}.
-	 * <br />
+	 * {@link Subscription#cancel() canceled}. <br />
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used.
-	 * <br />
+	 * configured otherwise, an instance of {@link MappingMongoConverter} will be used. <br />
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
 	 *
@@ -1516,11 +1496,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Subscribe to a MongoDB <a href="https://docs.mongodb.com/manual/changeStreams/">Change Stream</a> for all events in
 	 * the configured default database via the reactive infrastructure. Use the optional provided {@link Aggregation} to
 	 * filter events. The stream will not be completed unless the {@link org.reactivestreams.Subscription} is
-	 * {@link Subscription#cancel() canceled}.
-	 * <br />
+	 * {@link Subscription#cancel() canceled}. <br />
 	 * The {@link ChangeStreamEvent#getBody()} is mapped to the {@literal resultType} while the
-	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload.
-	 * <br />
+	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload. <br />
 	 * Use {@link ChangeStreamOptions} to set arguments like {@link ChangeStreamOptions#getResumeToken() the resumseToken}
 	 * for resuming change streams.
 	 *
@@ -1540,11 +1518,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * Subscribe to a MongoDB <a href="https://docs.mongodb.com/manual/changeStreams/">Change Stream</a> for all events in
 	 * the given collection via the reactive infrastructure. Use the optional provided {@link Aggregation} to filter
 	 * events. The stream will not be completed unless the {@link org.reactivestreams.Subscription} is
-	 * {@link Subscription#cancel() canceled}.
-	 * <br />
+	 * {@link Subscription#cancel() canceled}. <br />
 	 * The {@link ChangeStreamEvent#getBody()} is mapped to the {@literal resultType} while the
-	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload.
-	 * <br />
+	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload. <br />
 	 * Use {@link ChangeStreamOptions} to set arguments like {@link ChangeStreamOptions#getResumeToken() the resumseToken}
 	 * for resuming change streams.
 	 *
@@ -1565,11 +1541,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	/**
 	 * Subscribe to a MongoDB <a href="https://docs.mongodb.com/manual/changeStreams/">Change Stream</a> via the reactive
 	 * infrastructure. Use the optional provided {@link Aggregation} to filter events. The stream will not be completed
-	 * unless the {@link org.reactivestreams.Subscription} is {@link Subscription#cancel() canceled}.
-	 * <br />
+	 * unless the {@link org.reactivestreams.Subscription} is {@link Subscription#cancel() canceled}. <br />
 	 * The {@link ChangeStreamEvent#getBody()} is mapped to the {@literal resultType} while the
-	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload.
-	 * <br />
+	 * {@link ChangeStreamEvent#getRaw()} contains the unmodified payload. <br />
 	 * Use {@link ChangeStreamOptions} to set arguments like {@link ChangeStreamOptions#getResumeToken() the resumseToken}
 	 * for resuming change streams.
 	 *
@@ -1599,7 +1573,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param options additional options like output collection. Must not be {@literal null}.
 	 * @return a {@link Flux} emitting the result document sequence. Never {@literal null}.
 	 * @since 2.1
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> Flux<T> mapReduce(Query filterQuery, Class<?> domainType, Class<T> resultType, String mapFunction,
 			String reduceFunction, MapReduceOptions options);
 
@@ -1617,7 +1593,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param options additional options like output collection. Must not be {@literal null}.
 	 * @return a {@link Flux} emitting the result document sequence. Never {@literal null}.
 	 * @since 2.1
+	 * @deprecated since 3.4 in favor of {@link #aggregate(TypedAggregation, Class)}.
 	 */
+	@Deprecated
 	<T> Flux<T> mapReduce(Query filterQuery, Class<?> domainType, String inputCollectionName, Class<T> resultType,
 			String mapFunction, String reduceFunction, MapReduceOptions options);
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveRemoveOperationSupport.java

@@ -41,10 +41,6 @@ class ReactiveRemoveOperationSupport implements ReactiveRemoveOperation {
 		this.tempate = tempate;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveRemoveOperation#remove(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveRemove<T> remove(Class<T> domainType) {
 
@@ -68,10 +64,6 @@ class ReactiveRemoveOperationSupport implements ReactiveRemoveOperation {
 			this.collection = collection;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveRemoveOperation.RemoveWithCollection#inCollection(String)
-		 */
 		@Override
 		public RemoveWithQuery<T> inCollection(String collection) {
 
@@ -80,10 +72,6 @@ class ReactiveRemoveOperationSupport implements ReactiveRemoveOperation {
 			return new ReactiveRemoveSupport<>(template, domainType, query, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveRemoveOperation.RemoveWithQuery#matching(org.springframework.data.mongodb.core.Query)
-		 */
 		@Override
 		public TerminatingRemove<T> matching(Query query) {
 
@@ -92,10 +80,6 @@ class ReactiveRemoveOperationSupport implements ReactiveRemoveOperation {
 			return new ReactiveRemoveSupport<>(template, domainType, query, collection);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveRemoveOperation.TerminatingRemove#all()
-		 */
 		@Override
 		public Mono<DeleteResult> all() {
 
@@ -104,10 +88,6 @@ class ReactiveRemoveOperationSupport implements ReactiveRemoveOperation {
 			return template.doRemove(collectionName, query, domainType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveRemoveOperation.TerminatingRemove#findAndRemove()
-		 */
 		@Override
 		public Flux<T> findAndRemove() {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveUpdateOperationSupport.java

@@ -42,10 +42,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 		this.template = template;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation#update(java.lang.Class)
-	 */
 	@Override
 	public <T> ReactiveUpdate<T> update(Class<T> domainType) {
 
@@ -83,10 +79,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 			this.targetType = targetType;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.UpdateWithUpdate#apply(org.springframework.data.mongodb.core.query.UpdateDefinition)
-		 */
 		@Override
 		public TerminatingUpdate<T> apply(org.springframework.data.mongodb.core.query.UpdateDefinition update) {
 
@@ -96,10 +88,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.UpdateWithCollection#inCollection(java.lang.String)
-		 */
 		@Override
 		public UpdateWithQuery<T> inCollection(String collection) {
 
@@ -109,28 +97,16 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.TerminatingUpdate#first()
-		 */
 		@Override
 		public Mono<UpdateResult> first() {
 			return doUpdate(false, false);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.TerminatingUpdate#upsert()
-		 */
 		@Override
 		public Mono<UpdateResult> upsert() {
 			return doUpdate(true, true);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.TerminatingFindAndModify#findAndModify()
-		 */
 		@Override
 		public Mono<T> findAndModify() {
 
@@ -141,10 +117,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					collectionName);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.TerminatingFindAndReplace#findAndReplace()
-		 */
 		@Override
 		public Mono<T> findAndReplace() {
 			return template.findAndReplace(query, replacement,
@@ -152,10 +124,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					getCollectionName(), targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.UpdateWithQuery#matching(org.springframework.data.mongodb.core.Query)
-		 */
 		@Override
 		public UpdateWithUpdate<T> matching(Query query) {
 
@@ -165,19 +133,11 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.TerminatingUpdate#all()
-		 */
 		@Override
 		public Mono<UpdateResult> all() {
 			return doUpdate(true, false);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.FindAndModifyWithOptions#withOptions(org.springframework.data.mongodb.core.FindAndModifyOptions)
-		 */
 		@Override
 		public TerminatingFindAndModify<T> withOptions(FindAndModifyOptions options) {
 
@@ -187,10 +147,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.UpdateWithUpdate#replaceWith(java.lang.Object)
-		 */
 		@Override
 		public FindAndReplaceWithProjection<T> replaceWith(T replacement) {
 
@@ -200,10 +156,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					findAndReplaceOptions, replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.FindAndReplaceWithOptions#withOptions(org.springframework.data.mongodb.core.FindAndReplaceOptions)
-		 */
 		@Override
 		public FindAndReplaceWithProjection<T> withOptions(FindAndReplaceOptions options) {
 
@@ -213,10 +165,6 @@ class ReactiveUpdateOperationSupport implements ReactiveUpdateOperation {
 					replacement, targetType);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.ReactiveUpdateOperation.FindAndReplaceWithProjection#as(java.lang.Class)
-		 */
 		@Override
 		public <R> FindAndReplaceWithOptions<R> as(Class<R> resultType) {
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleMongoClientDatabaseFactory.java

@@ -75,28 +75,16 @@ public class SimpleMongoClientDatabaseFactory extends MongoDatabaseFactorySuppor
 		super(mongoClient, databaseName, mongoInstanceCreated, new MongoExceptionTranslator());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
-	 */
 	@Override
 	public ClientSession getSession(ClientSessionOptions options) {
 		return getMongoClient().startSession(options);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#closeClient()
-	 */
 	@Override
 	protected void closeClient() {
 		getMongoClient().close();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#doGetMongoDatabase(java.lang.String)
-	 */
 	@Override
 	protected MongoDatabase doGetMongoDatabase(String dbName) {
 		return getMongoClient().getDatabase(dbName);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleMongoClientDbFactory.java

@@ -1,74 +0,0 @@
-/*
- * Copyright 2018-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.data.mongodb.core;
-
-import com.mongodb.ConnectionString;
-import com.mongodb.client.MongoClient;
-import com.mongodb.client.MongoClients;
-import com.mongodb.client.MongoDatabase;
-
-/**
- * Factory to create {@link MongoDatabase} instances from a {@link MongoClient} instance.
- *
- * @author Christoph Strobl
- * @since 2.1
- * @deprecated since 3.0, use {@link SimpleMongoClientDatabaseFactory} instead.
- */
-@Deprecated
-public class SimpleMongoClientDbFactory extends SimpleMongoClientDatabaseFactory {
-
-	/**
-	 * Creates a new {@link SimpleMongoClientDbFactory} instance for the given {@code connectionString}.
-	 *
-	 * @param connectionString connection coordinates for a database connection. Must contain a database name and must not
-	 *          be {@literal null} or empty.
-	 * @see <a href="https://docs.mongodb.com/manual/reference/connection-string/">MongoDB Connection String reference</a>
-	 */
-	public SimpleMongoClientDbFactory(String connectionString) {
-		this(new ConnectionString(connectionString));
-	}
-
-	/**
-	 * Creates a new {@link SimpleMongoClientDbFactory} instance from the given {@link MongoClient}.
-	 *
-	 * @param connectionString connection coordinates for a database connection. Must contain also a database name and not
-	 *          be {@literal null}.
-	 */
-	public SimpleMongoClientDbFactory(ConnectionString connectionString) {
-		this(MongoClients.create(connectionString), connectionString.getDatabase(), true);
-	}
-
-	/**
-	 * Creates a new {@link SimpleMongoClientDbFactory} instance from the given {@link MongoClient}.
-	 *
-	 * @param mongoClient must not be {@literal null}.
-	 * @param databaseName must not be {@literal null} or empty.
-	 */
-	public SimpleMongoClientDbFactory(MongoClient mongoClient, String databaseName) {
-		this(mongoClient, databaseName, false);
-	}
-
-	/**
-	 * Creates a new {@link SimpleMongoClientDbFactory} instance from the given {@link MongoClient}.
-	 *
-	 * @param mongoClient must not be {@literal null}.
-	 * @param databaseName must not be {@literal null} or empty.
-	 * @param mongoInstanceCreated
-	 */
-	private SimpleMongoClientDbFactory(MongoClient mongoClient, String databaseName, boolean mongoInstanceCreated) {
-		super(mongoClient, databaseName, mongoInstanceCreated);
-	}
-}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleReactiveMongoDatabaseFactory.java

@@ -97,18 +97,10 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 		this.writeConcern = writeConcern;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getMongoDatabase()
-	 */
 	public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
 		return getMongoDatabase(databaseName);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getMongoDatabase(java.lang.String)
-	 */
 	public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
 
 		Assert.hasText(dbName, "Database name must not be empty.");
@@ -133,36 +125,20 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 		}
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getExceptionTranslator()
-	 */
 	public PersistenceExceptionTranslator getExceptionTranslator() {
 		return this.exceptionTranslator;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getCodecRegistry()
-	 */
 	@Override
 	public CodecRegistry getCodecRegistry() {
 		return this.mongo.getDatabase(databaseName).getCodecRegistry();
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
-	 */
 	@Override
 	public Mono<ClientSession> getSession(ClientSessionOptions options) {
 		return Mono.from(mongo.startSession(options));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#withSession(com.mongodb.session.ClientSession)
-	 */
 	@Override
 	public ReactiveMongoDatabaseFactory withSession(ClientSession session) {
 		return new ClientSessionBoundMongoDbFactory(session, this);
@@ -186,64 +162,36 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 			this.delegate = delegate;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getMongoDatabase()
-		 */
 		@Override
 		public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
 			return delegate.getMongoDatabase().map(this::decorateDatabase);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getMongoDatabase(java.lang.String)
-		 */
 		@Override
 		public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
 			return delegate.getMongoDatabase(dbName).map(this::decorateDatabase);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getExceptionTranslator()
-		 */
 		@Override
 		public PersistenceExceptionTranslator getExceptionTranslator() {
 			return delegate.getExceptionTranslator();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getCodecRegistry()
-		 */
 		@Override
 		public CodecRegistry getCodecRegistry() {
 			return delegate.getCodecRegistry();
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getSession(com.mongodb.ClientSessionOptions)
-		 */
 		@Override
 		public Mono<ClientSession> getSession(ClientSessionOptions options) {
 			return delegate.getSession(options);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#withSession(com.mongodb.session.ClientSession)
-		 */
 		@Override
 		public ReactiveMongoDatabaseFactory withSession(ClientSession session) {
 			return delegate.withSession(session);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#isTransactionActive()
-		 */
 		@Override
 		public boolean isTransactionActive() {
 			return session != null && session.hasActiveTransaction();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AbstractAggregationExpression.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022. the original author or authors.
+ * Copyright 2016-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -44,9 +44,6 @@ abstract class AbstractAggregationExpression implements AggregationExpression {
 		this.value = value;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 		return toDocument(this.value, context);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AccumulatorOperators.java

@@ -142,11 +142,118 @@ public class AccumulatorOperators {
 			return usesFieldRef() ? StdDevSamp.stdDevSampOf(fieldReference) : StdDevSamp.stdDevSampOf(expression);
 		}
 
+		/**
+		 * Creates new {@link AggregationExpression} that uses the previous input (field/expression) and the value of the
+		 * given field to calculate the population covariance of the two.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 * @since 3.3
+		 */
+		public CovariancePop covariancePop(String fieldReference) {
+			return covariancePop().and(fieldReference);
+		}
+
+		/**
+		 * Creates new {@link AggregationExpression} that uses the previous input (field/expression) and the result of the
+		 * given {@link AggregationExpression expression} to calculate the population covariance of the two.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 * @since 3.3
+		 */
+		public CovariancePop covariancePop(AggregationExpression expression) {
+			return covariancePop().and(expression);
+		}
+
+		private CovariancePop covariancePop() {
+			return usesFieldRef() ? CovariancePop.covariancePopOf(fieldReference) : CovariancePop.covariancePopOf(expression);
+		}
+
+		/**
+		 * Creates new {@link AggregationExpression} that uses the previous input (field/expression) and the value of the
+		 * given field to calculate the sample covariance of the two.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 * @since 3.3
+		 */
+		public CovarianceSamp covarianceSamp(String fieldReference) {
+			return covarianceSamp().and(fieldReference);
+		}
+
+		/**
+		 * Creates new {@link AggregationExpression} that uses the previous input (field/expression) and the result of the
+		 * given {@link AggregationExpression expression} to calculate the sample covariance of the two.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 * @since 3.3
+		 */
+		public CovarianceSamp covarianceSamp(AggregationExpression expression) {
+			return covarianceSamp().and(expression);
+		}
+
+		private CovarianceSamp covarianceSamp() {
+			return usesFieldRef() ? CovarianceSamp.covarianceSampOf(fieldReference)
+					: CovarianceSamp.covarianceSampOf(expression);
+		}
+
+		/**
+		 * Creates new {@link ExpMovingAvgBuilder} that to build {@link AggregationExpression expMovingAvg} that calculates
+		 * the exponential moving average of numeric values
+		 *
+		 * @return new instance of {@link ExpMovingAvg}.
+		 * @since 3.3
+		 */
+		public ExpMovingAvgBuilder expMovingAvg() {
+
+			ExpMovingAvg expMovingAvg = usesFieldRef() ? ExpMovingAvg.expMovingAvgOf(fieldReference)
+					: ExpMovingAvg.expMovingAvgOf(expression);
+			return new ExpMovingAvgBuilder() {
+
+				@Override
+				public ExpMovingAvg historicalDocuments(int numberOfHistoricalDocuments) {
+					return expMovingAvg.n(numberOfHistoricalDocuments);
+				}
+
+				@Override
+				public ExpMovingAvg alpha(double exponentialDecayValue) {
+					return expMovingAvg.alpha(exponentialDecayValue);
+				}
+			};
+		}
+
 		private boolean usesFieldRef() {
 			return fieldReference != null;
 		}
 	}
 
+	/**
+	 * Builder for {@link ExpMovingAvg}.
+	 *
+	 * @since 3.3
+	 */
+	public interface ExpMovingAvgBuilder {
+
+		/**
+		 * Define the number of historical documents with significant mathematical weight.
+		 *
+		 * @param numberOfHistoricalDocuments
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		ExpMovingAvg historicalDocuments(int numberOfHistoricalDocuments);
+
+		/**
+		 * Define the exponential decay value.
+		 *
+		 * @param exponentialDecayValue
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		ExpMovingAvg alpha(double exponentialDecayValue);
+
+	}
+
 	/**
 	 * {@link AggregationExpression} for {@code $sum}.
 	 *
@@ -227,9 +334,6 @@ public class AccumulatorOperators {
 			return new Sum(append(value));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -310,9 +414,6 @@ public class AccumulatorOperators {
 			return new Avg(append(expression));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -393,9 +494,6 @@ public class AccumulatorOperators {
 			return new Max(append(expression));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -476,9 +574,6 @@ public class AccumulatorOperators {
 			return new Min(append(expression));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -559,9 +654,6 @@ public class AccumulatorOperators {
 			return new StdDevPop(append(expression));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -642,9 +734,6 @@ public class AccumulatorOperators {
 			return new StdDevSamp(append(expression));
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AccumulatorOperators.AbstractAggregationExpression#toDocument(java.lang.Object, org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		@SuppressWarnings("unchecked")
 		public Document toDocument(Object value, AggregationOperationContext context) {
@@ -658,4 +747,185 @@ public class AccumulatorOperators {
 			return super.toDocument(value, context);
 		}
 	}
+
+	/**
+	 * {@link AggregationExpression} for {@code $covariancePop}.
+	 *
+	 * @author Christoph Strobl
+	 * @since 3.3
+	 */
+	public static class CovariancePop extends AbstractAggregationExpression {
+
+		private CovariancePop(Object value) {
+			super(value);
+		}
+
+		/**
+		 * Creates new {@link CovariancePop}.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 */
+		public static CovariancePop covariancePopOf(String fieldReference) {
+
+			Assert.notNull(fieldReference, "FieldReference must not be null!");
+			return new CovariancePop(asFields(fieldReference));
+		}
+
+		/**
+		 * Creates new {@link CovariancePop}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 */
+		public static CovariancePop covariancePopOf(AggregationExpression expression) {
+			return new CovariancePop(Collections.singletonList(expression));
+		}
+
+		/**
+		 * Creates new {@link CovariancePop} with all previously added arguments appending the given one.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 */
+		public CovariancePop and(String fieldReference) {
+			return new CovariancePop(append(asFields(fieldReference)));
+		}
+
+		/**
+		 * Creates new {@link CovariancePop} with all previously added arguments appending the given one.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovariancePop}.
+		 */
+		public CovariancePop and(AggregationExpression expression) {
+			return new CovariancePop(append(expression));
+		}
+
+		@Override
+		protected String getMongoMethod() {
+			return "$covariancePop";
+		}
+	}
+
+	/**
+	 * {@link AggregationExpression} for {@code $covarianceSamp}.
+	 *
+	 * @author Christoph Strobl
+	 * @since 3.3
+	 */
+	public static class CovarianceSamp extends AbstractAggregationExpression {
+
+		private CovarianceSamp(Object value) {
+			super(value);
+		}
+
+		/**
+		 * Creates new {@link CovarianceSamp}.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovarianceSamp}.
+		 */
+		public static CovarianceSamp covarianceSampOf(String fieldReference) {
+
+			Assert.notNull(fieldReference, "FieldReference must not be null!");
+			return new CovarianceSamp(asFields(fieldReference));
+		}
+
+		/**
+		 * Creates new {@link CovarianceSamp}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovarianceSamp}.
+		 */
+		public static CovarianceSamp covarianceSampOf(AggregationExpression expression) {
+			return new CovarianceSamp(Collections.singletonList(expression));
+		}
+
+		/**
+		 * Creates new {@link CovarianceSamp} with all previously added arguments appending the given one.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link CovarianceSamp}.
+		 */
+		public CovarianceSamp and(String fieldReference) {
+			return new CovarianceSamp(append(asFields(fieldReference)));
+		}
+
+		/**
+		 * Creates new {@link CovarianceSamp} with all previously added arguments appending the given one.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link CovarianceSamp}.
+		 */
+		public CovarianceSamp and(AggregationExpression expression) {
+			return new CovarianceSamp(append(expression));
+		}
+
+		@Override
+		protected String getMongoMethod() {
+			return "$covarianceSamp";
+		}
+	}
+
+	/**
+	 * {@link ExpMovingAvg} calculates the exponential moving average of numeric values.
+	 *
+	 * @author Christoph Strobl
+	 * @since 3.3
+	 */
+	public static class ExpMovingAvg extends AbstractAggregationExpression {
+
+		private ExpMovingAvg(Object value) {
+			super(value);
+		}
+
+		/**
+		 * Create a new {@link ExpMovingAvg} by defining the field holding the value to be used as input.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		public static ExpMovingAvg expMovingAvgOf(String fieldReference) {
+			return new ExpMovingAvg(Collections.singletonMap("input", Fields.field(fieldReference)));
+		}
+
+		/**
+		 * Create a new {@link ExpMovingAvg} by defining the {@link AggregationExpression expression} to compute the value
+		 * to be used as input.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		public static ExpMovingAvg expMovingAvgOf(AggregationExpression expression) {
+			return new ExpMovingAvg(Collections.singletonMap("input", expression));
+		}
+
+		/**
+		 * Define the number of historical documents with significant mathematical weight. <br />
+		 * Specify either {@link #n(int) N} or {@link #alpha(double) aplha}. Not both!
+		 *
+		 * @param numberOfHistoricalDocuments
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		public ExpMovingAvg n/*umber of historical documents*/(int numberOfHistoricalDocuments) {
+			return new ExpMovingAvg(append("N", numberOfHistoricalDocuments));
+		}
+
+		/**
+		 * Define the exponential decay value. <br />
+		 * Specify either {@link #alpha(double) aplha} or {@link #n(int) N}. Not both!
+		 *
+		 * @param exponentialDecayValue
+		 * @return new instance of {@link ExpMovingAvg}.
+		 */
+		public ExpMovingAvg alpha(double exponentialDecayValue) {
+			return new ExpMovingAvg(append("alpha", exponentialDecayValue));
+		}
+
+		@Override
+		protected String getMongoMethod() {
+			return "$expMovingAvg";
+		}
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AddFieldsOperation.java

@@ -99,10 +99,6 @@ public class AddFieldsOperation extends DocumentEnhancingOperation {
 		return new AddFieldsOperationBuilder(getValueMap());
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.DocumentEnhancingOperation#mongoOperator()
-	 */
 	@Override
 	protected String mongoOperator() {
 		return "$addFields";
@@ -201,4 +197,5 @@ public class AddFieldsOperation extends DocumentEnhancingOperation {
 			AddFieldsOperationBuilder withValueOfExpression(String operation, Object... values);
 		}
 	}
+
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java

@@ -226,8 +226,7 @@ public class Aggregation {
 	}
 
 	/**
-	 * Obtain an {@link AddFieldsOperationBuilder builder} instance to create a new {@link AddFieldsOperation}.
-	 * <br />
+	 * Obtain an {@link AddFieldsOperationBuilder builder} instance to create a new {@link AddFieldsOperation}. <br />
 	 * Starting in version 4.2, MongoDB adds a new aggregation pipeline stage {@link AggregationUpdate#set $set} that is
 	 * an alias for {@code $addFields}.
 	 *
@@ -435,18 +434,6 @@ public class Aggregation {
 		return new SortByCountOperation(groupAndSortExpression);
 	}
 
-	/**
-	 * Creates a new {@link SkipOperation} skipping the given number of elements.
-	 *
-	 * @param elementsToSkip must not be less than zero.
-	 * @return new instance of {@link SkipOperation}.
-	 * @deprecated prepare to get this one removed in favor of {@link #skip(long)}.
-	 */
-	@Deprecated
-	public static SkipOperation skip(int elementsToSkip) {
-		return new SkipOperation(elementsToSkip);
-	}
-
 	/**
 	 * Creates a new {@link SkipOperation} skipping the given number of elements.
 	 *
@@ -499,6 +486,17 @@ public class Aggregation {
 		return new MatchOperation(criteria);
 	}
 
+	/**
+	 * Creates a new {@link MatchOperation} using the given {@link AggregationExpression}.
+	 *
+	 * @param expression must not be {@literal null}.
+	 * @return new instance of {@link MatchOperation}.
+	 * @since 3.3
+	 */
+	public static MatchOperation match(AggregationExpression expression) {
+		return new MatchOperation(expression);
+	}
+
 	/**
 	 * Creates a new {@link GeoNearOperation} instance from the given {@link NearQuery} and the {@code distanceField}. The
 	 * {@code distanceField} defines output field that contains the calculated distance.
@@ -714,8 +712,7 @@ public class Aggregation {
 	}
 
 	/**
-	 * Converts this {@link Aggregation} specification to a {@link Document}.
-	 * <br />
+	 * Converts this {@link Aggregation} specification to a {@link Document}. <br />
 	 * MongoDB requires as of 3.6 cursor-based aggregation. Use {@link #toPipeline(AggregationOperationContext)} to render
 	 * an aggregation pipeline.
 	 *
@@ -730,10 +727,6 @@ public class Aggregation {
 		return options.applyAndReturnPotentiallyChangedCommand(command);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.lang.Object#toString()
-	 */
 	@Override
 	public String toString() {
 		return SerializationUtils.serializeToJsonSafely(toDocument("__collection__", DEFAULT_CONTEXT));
@@ -777,10 +770,6 @@ public class Aggregation {
 			return false;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see java.lang.Enum#toString()
-		 */
 		@Override
 		public String toString() {
 			return PREFIX.concat(name());

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationFunctionExpressions.java

@@ -1,108 +0,0 @@
-/*
- * Copyright 2015-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.springframework.data.mongodb.core.aggregation;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
-import org.bson.Document;
-import org.springframework.util.Assert;
-
-/**
- * An enum of supported {@link AggregationExpression}s in aggregation pipeline stages.
- *
- * @author Thomas Darimont
- * @author Oliver Gierke
- * @author Christoph Strobl
- * @author Mark Paluch
- * @since 1.7
- * @deprecated since 1.10. Please use {@link ArithmeticOperators} and {@link ComparisonOperators} instead.
- */
-@Deprecated
-public enum AggregationFunctionExpressions {
-
-	SIZE, CMP, EQ, GT, GTE, LT, LTE, NE, SUBTRACT, ADD, MULTIPLY;
-
-	/**
-	 * Returns an {@link AggregationExpression} build from the current {@link Enum} name and the given parameters.
-	 *
-	 * @param parameters must not be {@literal null}
-	 * @return new instance of {@link AggregationExpression}.
-	 */
-	public AggregationExpression of(Object... parameters) {
-
-		Assert.notNull(parameters, "Parameters must not be null!");
-		return new FunctionExpression(name().toLowerCase(), parameters);
-	}
-
-	/**
-	 * An {@link AggregationExpression} representing a function call.
-	 *
-	 * @author Thomas Darimont
-	 * @author Oliver Gierke
-	 * @since 1.7
-	 */
-	static class FunctionExpression implements AggregationExpression {
-
-		private final String name;
-		private final List<Object> values;
-
-		/**
-		 * Creates a new {@link FunctionExpression} for the given name and values.
-		 *
-		 * @param name must not be {@literal null} or empty.
-		 * @param values must not be {@literal null}.
-		 */
-		public FunctionExpression(String name, Object[] values) {
-
-			Assert.hasText(name, "Name must not be null!");
-			Assert.notNull(values, "Values must not be null!");
-
-			this.name = name;
-			this.values = Arrays.asList(values);
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.Expression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
-		@Override
-		public Document toDocument(AggregationOperationContext context) {
-
-			List<Object> args = new ArrayList<Object>(values.size());
-
-			for (Object value : values) {
-				args.add(unpack(value, context));
-			}
-
-			return new Document("$" + name, args);
-		}
-
-		private static Object unpack(Object value, AggregationOperationContext context) {
-
-			if (value instanceof AggregationExpression) {
-				return ((AggregationExpression) value).toDocument(context);
-			}
-
-			if (value instanceof Field) {
-				return context.getReference((Field) value).toString();
-			}
-
-			return value;
-		}
-	}
-}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperationRenderer.java

@@ -80,28 +80,16 @@ class AggregationOperationRenderer {
 	 */
 	private static class NoOpAggregationOperationContext implements AggregationOperationContext {
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getMappedObject(org.bson.Document, java.lang.Class)
-		 */
 		@Override
 		public Document getMappedObject(Document document, @Nullable Class<?> type) {
 			return document;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(org.springframework.data.mongodb.core.aggregation.ExposedFields.AvailableField)
-		 */
 		@Override
 		public FieldReference getReference(Field field) {
 			return new DirectFieldReference(new ExposedField(field, true));
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
-		 */
 		@Override
 		public FieldReference getReference(String name) {
 			return new DirectFieldReference(new ExposedField(new AggregationField(name), true));

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOptions.java

@@ -339,9 +339,6 @@ public class AggregationOptions {
 		return !maxTime.isZero() && !maxTime.isNegative();
 	}
 
-	/* (non-Javadoc)
-	 * @see java.lang.Object#toString()
-	 */
 	@Override
 	public String toString() {
 		return toDocument().toJson();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java

@@ -77,10 +77,6 @@ public class AggregationResults<T> implements Iterable<T> {
 		return mappedResults.size() == 1 ? mappedResults.get(0) : null;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see java.lang.Iterable#iterator()
-	 */
 	public Iterator<T> iterator() {
 		return mappedResults.iterator();
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationSpELExpression.java

@@ -64,9 +64,6 @@ public class AggregationSpELExpression implements AggregationExpression {
 		return new AggregationSpELExpression(expressionString, parameters);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 		return (Document) TRANSFORMER.transform(rawExpression, context, parameters);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationUpdate.java

@@ -242,48 +242,26 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 		return this;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#isIsolated()
-	 */
 	@Override
 	public Boolean isIsolated() {
 		return isolated;
 	}
 
-	/*
-	 * Returns a update document containing the update pipeline.
-	 * The resulting document needs to be unwrapped to be used with update operations.
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#getUpdateObject()
-	 */
 	@Override
 	public Document getUpdateObject() {
 		return new Document("", toPipeline(Aggregation.DEFAULT_CONTEXT));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#modifies(java.lang.String)
-	 */
 	@Override
 	public boolean modifies(String key) {
 		return keysTouched.contains(key);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#inc(java.lang.String)
-	 */
 	@Override
 	public void inc(String key) {
 		set(new SetOperation(key, ArithmeticOperators.valueOf(key).add(1)));
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.query.UpdateDefinition#getArrayFilters()
-	 */
 	@Override
 	public List<ArrayFilter> getArrayFilters() {
 		return Collections.emptyList();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ArrayOperators.java

@@ -35,6 +35,7 @@ import org.springframework.util.Assert;
  * @author Christoph Strobl
  * @author Mark Paluch
  * @author Shashank Sharma
+ * @author Divya Srivastava
  * @since 1.0
  */
 public class ArrayOperators {
@@ -362,6 +363,38 @@ public class ArrayOperators {
 
 			return usesExpression() ? ArrayToObject.arrayValueOfToObject(expression) : ArrayToObject.arrayToObject(values);
 		}
+		
+		/**
+		 * Creates new {@link AggregationExpression} that return the first element in the associated array.
+		 * <strong>NOTE:</strong> Requires MongoDB 4.4 or later.
+		 *
+		 * @return new instance of {@link First}.
+		 * @since 3.4
+		 */
+		public First first() {
+
+			if (usesFieldRef()) {
+				return First.firstOf(fieldReference);
+			}
+
+			return usesExpression() ? First.firstOf(expression) : First.first(values);
+		}
+		
+		/**
+		 * Creates new {@link AggregationExpression} that return the last element in the given array.
+		 * <strong>NOTE:</strong> Requires MongoDB 4.4 or later.
+		 *
+		 * @return new instance of {@link Last}.
+		 * @since 3.4
+		 */
+		public Last last() {
+
+			if (usesFieldRef()) {
+				return Last.lastOf(fieldReference);
+			}
+
+			return usesExpression() ? Last.lastOf(expression) : Last.last(values);
+		}
 
 		/**
 		 * @author Christoph Strobl
@@ -612,10 +645,6 @@ public class ArrayOperators {
 			return new FilterExpressionBuilder().filter(values);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(final AggregationOperationContext context) {
 			return toFilter(ExposedFields.from(as), context);
@@ -736,10 +765,6 @@ public class ArrayOperators {
 				return new FilterExpressionBuilder();
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.InputBuilder#filter(java.util.List)
-			 */
 			@Override
 			public AsBuilder filter(List<?> array) {
 
@@ -748,10 +773,6 @@ public class ArrayOperators {
 				return this;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.InputBuilder#filter(org.springframework.data.mongodb.core.aggregation.Field)
-			 */
 			@Override
 			public AsBuilder filter(Field field) {
 
@@ -760,10 +781,6 @@ public class ArrayOperators {
 				return this;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.AsBuilder#as(java.lang.String)
-			 */
 			@Override
 			public ConditionBuilder as(String variableName) {
 
@@ -772,10 +789,6 @@ public class ArrayOperators {
 				return this;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.ConditionBuilder#by(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			@Override
 			public Filter by(AggregationExpression condition) {
 
@@ -784,10 +797,6 @@ public class ArrayOperators {
 				return filter;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.ConditionBuilder#by(java.lang.String)
-			 */
 			@Override
 			public Filter by(String expression) {
 
@@ -796,10 +805,6 @@ public class ArrayOperators {
 				return filter;
 			}
 
-			/*
-			 * (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ArrayOperators.Filter.ConditionBuilder#by(org.bson.Document)
-			 */
 			@Override
 			public Filter by(Document expression) {
 
@@ -1244,9 +1249,6 @@ public class ArrayOperators {
 			this.reduceExpressions = reduceExpressions;
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 
@@ -1433,9 +1435,6 @@ public class ArrayOperators {
 				};
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-			 */
 			@Override
 			public Document toDocument(AggregationOperationContext context) {
 				return new Document(propertyName, aggregationExpression.toDocument(context));
@@ -1803,13 +1802,117 @@ public class ArrayOperators {
 			return new ArrayToObject(expression);
 		}
 
+		@Override
+		protected String getMongoMethod() {
+			return "$arrayToObject";
+		}
+	}
+	
+	/**
+	 * {@link AggregationExpression} for {@code $first} that returns the first element in an array. <br />
+	 * <strong>NOTE:</strong> Requires MongoDB 4.4 or later.
+	 *
+	 * @author Divya Srivastava
+	 * @author Christoph Strobl
+	 * @since 3.4
+	 */
+	public static class First extends AbstractAggregationExpression {
+
+		private First(Object value) {
+			super(value);
+		}
+
+		/**
+		 * Returns the first element in the given array.
+		 *
+		 * @param array must not be {@literal null}.
+		 * @return new instance of {@link First}.
+		 */
+		public static First first(Object array) {
+			return new First(array);
+		}
+
+		/**
+		 * Returns the first element in the array pointed to by the given {@link Field field reference}.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link First}.
+		 */
+		public static First firstOf(String fieldReference) {
+			return new First(Fields.field(fieldReference));
+		}
+
+		/**
+		 * Returns the first element of the array computed by the given {@link AggregationExpression expression}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link First}.
+		 */
+		public static First firstOf(AggregationExpression expression) {
+			return new First(expression);
+		}
+
 		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.core.aggregation.AbstractAggregationExpression#getMongoMethod()
 		 */
 		@Override
 		protected String getMongoMethod() {
-			return "$arrayToObject";
+			return "$first";
+		}
+	}
+	
+	/**
+	 * {@link AggregationExpression} for {@code $last} that returns the last element in an array. <br />
+	 * <strong>NOTE:</strong> Requires MongoDB 4.4 or later.
+	 *
+	 * @author Divya Srivastava
+	 * @author Christoph Strobl
+	 * @since 3.4
+	 */
+	public static class Last extends AbstractAggregationExpression {
+
+		private Last(Object value) {
+			super(value);
+		}
+
+		/**
+		 * Returns the last element in the given array.
+		 *
+		 * @param array must not be {@literal null}.
+		 * @return new instance of {@link Last}.
+		 */
+		public static Last last(Object array) {
+			return new Last(array);
+		}
+
+		/**
+		 * Returns the last element in the array pointed to by the given {@link Field field reference}.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Last}.
+		 */
+		public static Last lastOf(String fieldReference) {
+			return new Last(Fields.field(fieldReference));
+		}
+
+		/**
+		 * Returns the last element of the array computed buy the given {@link AggregationExpression expression}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Last}.
+		 */
+		public static Last lastOf(AggregationExpression expression) {
+			return new Last(expression);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AbstractAggregationExpression#getMongoMethod()
+		 */
+		@Override
+		protected String getMongoMethod() {
+			return "$last";
 		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketAutoOperation.java

@@ -88,9 +88,6 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 		this.granularity = granularity;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 
@@ -107,10 +104,6 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 		return new Document(getOperator(), options);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
-	 */
 	@Override
 	public String getOperator() {
 		return "$bucketAuto";
@@ -144,33 +137,21 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 		return new BucketAutoOperation(this, buckets, granularity.getMongoRepresentation());
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#newBucketOperation(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.Outputs)
-	 */
 	@Override
 	protected BucketAutoOperation newBucketOperation(Outputs outputs) {
 		return new BucketAutoOperation(this, outputs);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutputExpression(java.lang.String, java.lang.Object[])
-	 */
 	@Override
 	public ExpressionBucketAutoOperationBuilder andOutputExpression(String expression, Object... params) {
 		return new ExpressionBucketAutoOperationBuilder(expression, this, params);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutput(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-	 */
 	@Override
 	public BucketAutoOperationOutputBuilder andOutput(AggregationExpression expression) {
 		return new BucketAutoOperationOutputBuilder(expression, this);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutput(java.lang.String)
-	 */
 	@Override
 	public BucketAutoOperationOutputBuilder andOutput(String fieldName) {
 		return new BucketAutoOperationOutputBuilder(Fields.field(fieldName), this);
@@ -192,9 +173,6 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 			super(value, operation);
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder#apply(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OperationOutput)
-		 */
 		@Override
 		protected BucketAutoOperationOutputBuilder apply(OperationOutput operationOutput) {
 			return new BucketAutoOperationOutputBuilder(operationOutput, this.operation);
@@ -223,9 +201,6 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 			super(expression, operation, parameters);
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder#apply(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OperationOutput)
-		 */
 		@Override
 		protected BucketAutoOperationOutputBuilder apply(OperationOutput operationOutput) {
 			return new BucketAutoOperationOutputBuilder(operationOutput, this.operation);
@@ -270,9 +245,6 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 			this.granularity = granularity;
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.GranularitytoMongoGranularity()
-		 */
 		@Override
 		public String getMongoRepresentation() {
 			return granularity;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperation.java

@@ -84,9 +84,6 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 		this.defaultBucket = defaultBucket;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 
@@ -103,10 +100,6 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 		return new Document(getOperator(), options);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
-	 */
 	@Override
 	public String getOperator() {
 		return "$bucket";
@@ -143,33 +136,21 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 		return new BucketOperation(this, newBoundaries, defaultBucket);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#newBucketOperation(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.Outputs)
-	 */
 	@Override
 	protected BucketOperation newBucketOperation(Outputs outputs) {
 		return new BucketOperation(this, outputs);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutputExpression(java.lang.String, java.lang.Object[])
-	 */
 	@Override
 	public ExpressionBucketOperationBuilder andOutputExpression(String expression, Object... params) {
 		return new ExpressionBucketOperationBuilder(expression, this, params);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutput(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-	 */
 	@Override
 	public BucketOperationOutputBuilder andOutput(AggregationExpression expression) {
 		return new BucketOperationOutputBuilder(expression, this);
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#andOutput(java.lang.String)
-	 */
 	@Override
 	public BucketOperationOutputBuilder andOutput(String fieldName) {
 		return new BucketOperationOutputBuilder(Fields.field(fieldName), this);
@@ -191,9 +172,6 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 			super(value, operation);
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder#apply(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OperationOutput)
-		 */
 		@Override
 		protected BucketOperationOutputBuilder apply(OperationOutput operationOutput) {
 			return new BucketOperationOutputBuilder(operationOutput, this.operation);
@@ -221,9 +199,6 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 			super(expression, operation, parameters);
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder#apply(org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OperationOutput)
-		 */
 		@Override
 		protected BucketOperationOutputBuilder apply(OperationOutput operationOutput) {
 			return new BucketOperationOutputBuilder(operationOutput, this.operation);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperationSupport.java

@@ -141,9 +141,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 		});
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 
@@ -159,9 +156,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 		return document;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#getFields()
-	 */
 	@Override
 	public ExposedFields getFields() {
 		return outputs.asExposedFields();
@@ -454,9 +448,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 			return outputs.isEmpty();
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 
@@ -540,10 +531,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 			this.values = operationOutput.values;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 
@@ -636,9 +623,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 			this.params = parameters.clone();
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.Output#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 			return (Document) TRANSFORMER.transform(expression, context, params);
@@ -665,9 +649,6 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 			this.expression = expression;
 		}
 
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.Output#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 			return expression.toDocument(context);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ConditionalOperators.java

@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core.aggregation;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
@@ -235,7 +236,7 @@ public class ConditionalOperators {
 	 *
 	 * @author Mark Paluch
 	 * @see <a href=
-	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/ifNull/">https://docs.mongodb.com/manual/reference/operator/aggregation/ifNull/</a>
+	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/ifNull/">https://docs.mongodb.com/manual/reference/operator/aggregation/ifNull/</a>
 	 */
 	public static class IfNull implements AggregationExpression {
 
@@ -251,7 +252,8 @@ public class ConditionalOperators {
 		/**
 		 * Creates new {@link IfNull}.
 		 *
-		 * @param fieldReference the field to check for a {@literal null} value, field reference must not be {@literal null}.
+		 * @param fieldReference the field to check for a {@literal null} value, field reference must not be
+		 *          {@literal null}.
 		 * @return never {@literal null}.
 		 */
 		public static ThenBuilder ifNull(String fieldReference) {
@@ -264,7 +266,7 @@ public class ConditionalOperators {
 		 * Creates new {@link IfNull}.
 		 *
 		 * @param expression the expression to check for a {@literal null} value, field reference must not be
-		 * {@literal null}.
+		 *          {@literal null}.
 		 * @return never {@literal null}.
 		 */
 		public static ThenBuilder ifNull(AggregationExpression expression) {
@@ -273,28 +275,34 @@ public class ConditionalOperators {
 			return new IfNullOperatorBuilder().ifNull(expression);
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 
 			List<Object> list = new ArrayList<Object>();
 
-			if (condition instanceof Field) {
-				list.add(context.getReference((Field) condition).toString());
-			} else if (condition instanceof AggregationExpression) {
-				list.add(((AggregationExpression) condition).toDocument(context));
+			if (condition instanceof Collection) {
+				for (Object val : ((Collection) this.condition)) {
+					list.add(mapCondition(val, context));
+				}
 			} else {
-				list.add(condition);
+				list.add(mapCondition(condition, context));
 			}
 
 			list.add(resolve(value, context));
-
 			return new Document("$ifNull", list);
 		}
 
+		private Object mapCondition(Object condition, AggregationOperationContext context) {
+
+			if (condition instanceof Field) {
+				return context.getReference((Field) condition).toString();
+			} else if (condition instanceof AggregationExpression) {
+				return ((AggregationExpression) condition).toDocument(context);
+			} else {
+				return condition;
+			}
+		}
+
 		private Object resolve(Object value, AggregationOperationContext context) {
 
 			if (value instanceof Field) {
@@ -315,28 +323,48 @@ public class ConditionalOperators {
 
 			/**
 			 * @param fieldReference the field to check for a {@literal null} value, field reference must not be
-			 * {@literal null}.
+			 *          {@literal null}.
 			 * @return the {@link ThenBuilder}
 			 */
 			ThenBuilder ifNull(String fieldReference);
 
 			/**
 			 * @param expression the expression to check for a {@literal null} value, field name must not be {@literal null}
-			 * or empty.
-			 * @return the {@link ThenBuilder}
+			 *          or empty.
+			 * @return the {@link ThenBuilder}.
 			 */
 			ThenBuilder ifNull(AggregationExpression expression);
 		}
 
+		/**
+		 * @author Christoph Strobl
+		 * @since 3.3
+		 */
+		public interface OrBuilder {
+
+			/**
+			 * @param fieldReference the field to check for a {@literal null} value, field reference must not be
+			 *          {@literal null}.
+			 * @return the {@link ThenBuilder}
+			 */
+			ThenBuilder orIfNull(String fieldReference);
+
+			/**
+			 * @param expression the expression to check for a {@literal null} value,
+			 * @return the {@link ThenBuilder}.
+			 */
+			ThenBuilder orIfNull(AggregationExpression expression);
+		}
+
 		/**
 		 * @author Mark Paluch
 		 */
-		public interface ThenBuilder {
+		public interface ThenBuilder extends OrBuilder {
 
 			/**
 			 * @param value the value to be used if the {@code $ifNull} condition evaluates {@literal true}. Can be a
-			 * {@link Document}, a value that is supported by MongoDB or a value that can be converted to a MongoDB
-			 * representation but must not be {@literal null}.
+			 *          {@link Document}, a value that is supported by MongoDB or a value that can be converted to a MongoDB
+			 *          representation but must not be {@literal null}.
 			 * @return new instance of {@link IfNull}.
 			 */
 			IfNull then(Object value);
@@ -361,9 +389,10 @@ public class ConditionalOperators {
 		 */
 		static final class IfNullOperatorBuilder implements IfNullBuilder, ThenBuilder {
 
-			private @Nullable Object condition;
+			private @Nullable List<Object> conditions;
 
 			private IfNullOperatorBuilder() {
+				conditions = new ArrayList<>();
 			}
 
 			/**
@@ -375,50 +404,45 @@ public class ConditionalOperators {
 				return new IfNullOperatorBuilder();
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.IfNullBuilder#ifNull(java.lang.String)
-			 */
 			public ThenBuilder ifNull(String fieldReference) {
 
 				Assert.hasText(fieldReference, "FieldReference name must not be null or empty!");
-				this.condition = Fields.field(fieldReference);
+				this.conditions.add(Fields.field(fieldReference));
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.IfNullBuilder#ifNull(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			@Override
 			public ThenBuilder ifNull(AggregationExpression expression) {
 
 				Assert.notNull(expression, "AggregationExpression name must not be null or empty!");
-				this.condition = expression;
+				this.conditions.add(expression);
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.ThenBuilder#then(java.lang.Object)
-			 */
-			public IfNull then(Object value) {
-				return new IfNull(condition, value);
+			@Override
+			public ThenBuilder orIfNull(String fieldReference) {
+				return ifNull(fieldReference);
+			}
+
+			@Override
+			public ThenBuilder orIfNull(AggregationExpression expression) {
+				return ifNull(expression);
+			}
+
+			public IfNull then(Object value) {
+				return new IfNull(conditions, value);
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.ThenBuilder#thenValueOf(java.lang.String)
-			 */
 			public IfNull thenValueOf(String fieldReference) {
 
 				Assert.notNull(fieldReference, "FieldReference must not be null!");
-				return new IfNull(condition, Fields.field(fieldReference));
+				return new IfNull(conditions, Fields.field(fieldReference));
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.ThenBuilder#thenValueOf(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			public IfNull thenValueOf(AggregationExpression expression) {
 
 				Assert.notNull(expression, "Expression must not be null!");
-				return new IfNull(condition, expression);
+				return new IfNull(conditions, expression);
 			}
 		}
 	}
@@ -458,7 +482,7 @@ public class ConditionalOperators {
 		public static Switch switchCases(List<CaseOperator> conditions) {
 
 			Assert.notNull(conditions, "Conditions must not be null!");
-			return new Switch(Collections.<String, Object>singletonMap("branches", new ArrayList<CaseOperator>(conditions)));
+			return new Switch(Collections.<String, Object> singletonMap("branches", new ArrayList<CaseOperator>(conditions)));
 		}
 
 		/**
@@ -500,9 +524,6 @@ public class ConditionalOperators {
 				};
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-			 */
 			@Override
 			public Document toDocument(AggregationOperationContext context) {
 
@@ -545,7 +566,7 @@ public class ConditionalOperators {
 	 * @author Mark Paluch
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/cond/">https://docs.mongodb.com/manual/reference/operator/aggregation/cond/</a>
+	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/cond/">https://docs.mongodb.com/manual/reference/operator/aggregation/cond/</a>
 	 */
 	public static class Cond implements AggregationExpression {
 
@@ -590,10 +611,6 @@ public class ConditionalOperators {
 			this.otherwiseValue = otherwiseValue;
 		}
 
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
-		 */
 		@Override
 		public Document toDocument(AggregationOperationContext context) {
 
@@ -806,8 +823,8 @@ public class ConditionalOperators {
 
 			/**
 			 * @param value the value to be used if the condition evaluates {@literal true}. Can be a {@link Document}, a
-			 * value that is supported by MongoDB or a value that can be converted to a MongoDB representation but
-			 * must not be {@literal null}.
+			 *          value that is supported by MongoDB or a value that can be converted to a MongoDB representation but
+			 *          must not be {@literal null}.
 			 * @return the {@link OtherwiseBuilder}
 			 */
 			OtherwiseBuilder then(Object value);
@@ -832,8 +849,8 @@ public class ConditionalOperators {
 
 			/**
 			 * @param value the value to be used if the condition evaluates {@literal false}. Can be a {@link Document}, a
-			 * value that is supported by MongoDB or a value that can be converted to a MongoDB representation but
-			 * must not be {@literal null}.
+			 *          value that is supported by MongoDB or a value that can be converted to a MongoDB representation but
+			 *          must not be {@literal null}.
 			 * @return the {@link Cond}
 			 */
 			Cond otherwise(Object value);
@@ -861,8 +878,7 @@ public class ConditionalOperators {
 			private @Nullable Object condition;
 			private @Nullable Object thenValue;
 
-			private ConditionalExpressionBuilder() {
-			}
+			private ConditionalExpressionBuilder() {}
 
 			/**
 			 * Creates a new builder for {@link Cond}.
@@ -873,9 +889,6 @@ public class ConditionalOperators {
 				return new ConditionalExpressionBuilder();
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.WhenBuilder#when(org.bson.Document)
-			 */
 			@Override
 			public ConditionalExpressionBuilder when(Document booleanExpression) {
 
@@ -885,9 +898,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.WhenBuilder#when(org.springframework.data.mongodb.core.query.CriteriaDefinition)
-			 */
 			@Override
 			public ThenBuilder when(CriteriaDefinition criteria) {
 
@@ -896,9 +906,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.WhenBuilder#when(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			@Override
 			public ThenBuilder when(AggregationExpression expression) {
 
@@ -907,9 +914,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.WhenBuilder#when(java.lang.String)
-			 */
 			@Override
 			public ThenBuilder when(String booleanField) {
 
@@ -918,9 +922,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.ThenBuilder#then(java.lang.Object)
-			 */
 			@Override
 			public OtherwiseBuilder then(Object thenValue) {
 
@@ -929,9 +930,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.ThenBuilder#thenValueOf(java.lang.String)
-			 */
 			@Override
 			public OtherwiseBuilder thenValueOf(String fieldReference) {
 
@@ -940,9 +938,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.ThenBuilder#thenValueOf(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			@Override
 			public OtherwiseBuilder thenValueOf(AggregationExpression expression) {
 
@@ -951,9 +946,6 @@ public class ConditionalOperators {
 				return this;
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.OtherwiseBuilder#otherwise(java.lang.Object)
-			 */
 			@Override
 			public Cond otherwise(Object otherwiseValue) {
 
@@ -961,9 +953,6 @@ public class ConditionalOperators {
 				return new Cond(condition, thenValue, otherwiseValue);
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.OtherwiseBuilder#otherwiseValueOf(java.lang.String)
-			 */
 			@Override
 			public Cond otherwiseValueOf(String fieldReference) {
 
@@ -971,9 +960,6 @@ public class ConditionalOperators {
 				return new Cond(condition, thenValue, Fields.field(fieldReference));
 			}
 
-			/* (non-Javadoc)
-			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.Cond.OtherwiseBuilder#otherwiseValueOf(org.springframework.data.mongodb.core.aggregation.AggregationExpression)
-			 */
 			@Override
 			public Cond otherwiseValueOf(AggregationExpression expression) {