After release cleanups.

See #4206

.mvn/wrapper/maven-wrapper.properties

@@ -1,2 +1,2 @@
-#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
+#Fri Jun 03 09:42:19 CEST 2022
+distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.5/apache-maven-3.8.5-bin.zip

Jenkinsfile

@@ -9,7 +9,7 @@ pipeline {
 
 	triggers {
 		pollSCM 'H/10 * * * *'
-		upstream(upstreamProjects: "spring-data-commons/3.0.x", threshold: hudson.model.Result.SUCCESS)
+		upstream(upstreamProjects: "spring-data-commons/2.6.x", threshold: hudson.model.Result.SUCCESS)
 	}
 
 	options {
@@ -20,7 +20,64 @@ pipeline {
 	stages {
 		stage("Docker images") {
 			parallel {
-				stage('Publish JDK (Java 17) + MongoDB 4.4') {
+				stage('Publish JDK (main) + MongoDB 4.0') {
+					when {
+						anyOf {
+							changeset "ci/openjdk8-mongodb-4.0/**"
+							changeset "ci/pipeline.properties"
+						}
+					}
+					agent { label 'data' }
+					options { timeout(time: 30, unit: 'MINUTES') }
+
+					steps {
+						script {
+							def image = docker.build("springci/spring-data-with-mongodb-4.0:${p['java.main.tag']}", "--build-arg BASE=${p['docker.java.main.image']} --build-arg MONGODB=${p['docker.mongodb.4.0.version']} ci/openjdk8-mongodb-4.0/")
+							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
+								image.push()
+							}
+						}
+					}
+				}
+				stage('Publish JDK (main) + MongoDB 4.4') {
+					when {
+						anyOf {
+							changeset "ci/openjdk8-mongodb-4.4/**"
+							changeset "ci/pipeline.properties"
+						}
+					}
+					agent { label 'data' }
+					options { timeout(time: 30, unit: 'MINUTES') }
+
+					steps {
+						script {
+							def image = docker.build("springci/spring-data-with-mongodb-4.4:${p['java.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 (main) + MongoDB 5.0') {
+					when {
+						anyOf {
+							changeset "ci/openjdk8-mongodb-5.0/**"
+							changeset "ci/pipeline.properties"
+						}
+					}
+					agent { label 'data' }
+					options { timeout(time: 30, unit: 'MINUTES') }
+
+					steps {
+						script {
+							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/openjdk8-mongodb-5.0/")
+							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
+								image.push()
+							}
+						}
+					}
+				}
+				stage('Publish JDK (LTS) + MongoDB 4.4') {
 					when {
 						anyOf {
 							changeset "ci/openjdk17-mongodb-4.4/**"
@@ -32,26 +89,7 @@ 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=${p['docker.mongodb.4.4.version']} ci/openjdk17-mongodb-4.4/")
-							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
-								image.push()
-							}
-						}
-					}
-				}
-				stage('Publish JDK (Java 17) + MongoDB 5.0') {
-					when {
-						anyOf {
-							changeset "ci/openjdk17-mongodb-5.0/**"
-							changeset "ci/pipeline.properties"
-						}
-					}
-					agent { label 'data' }
-					options { timeout(time: 30, unit: 'MINUTES') }
-
-					steps {
-						script {
-							def image = docker.build("springci/spring-data-with-mongodb-5.0:${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/")
+							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/")
 							docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 								image.push()
 							}
@@ -61,7 +99,7 @@ pipeline {
 			}
 		}
 
-		stage("test: baseline (Java 17)") {
+		stage("test: baseline (main)") {
 			when {
 				beforeAgent(true)
 				anyOf {
@@ -78,15 +116,13 @@ 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:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
-							sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-							sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
-							sh 'sleep 10'
-							sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
-							sh 'sleep 15'
-							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
-						}
+					docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.0:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
+						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'
 					}
 				}
 			}
@@ -101,8 +137,7 @@ pipeline {
 				}
 			}
 			parallel {
-
-				stage("test: mongodb 5.0 (Java 17)") {
+				stage("test: mongodb 4.4 (main)") {
 					agent {
 						label 'data'
 					}
@@ -112,15 +147,57 @@ 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-5.0:${p['java.main.tag']}").inside(p['docker.java.inside.basic']) {
-									sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-									sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
-									sh 'sleep 10'
-									sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
-									sh 'sleep 15'
-									sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
-								}
+							docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.4:${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: mongodb 5.0 (main)") {
+					agent {
+						label 'data'
+					}
+					options { timeout(time: 30, unit: 'MINUTES') }
+					environment {
+						ARTIFACTORY = credentials("${p['artifactory.credentials']}")
+					}
+					steps {
+						script {
+							docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-5.0:${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'
+								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)") {
+					agent {
+						label 'data'
+					}
+					options { timeout(time: 30, unit: 'MINUTES') }
+					environment {
+						ARTIFACTORY = credentials("${p['artifactory.credentials']}")
+					}
+					steps {
+						script {
+							docker.image("harbor-repo.vmware.com/dockerhub-proxy-cache/springci/spring-data-with-mongodb-4.4:${p['java.lts.tag']}").inside(p['docker.java.inside.basic']) {
+								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'
 							}
 						}
 					}
@@ -147,18 +224,15 @@ pipeline {
 
 			steps {
 				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=${ARTIFACTORY_USR} " +
-									"-Dartifactory.password=${ARTIFACTORY_PSW} " +
-									"-Dartifactory.staging-repository=libs-snapshot-local " +
-									"-Dartifactory.build-name=spring-data-mongodb " +
-									"-Dartifactory.build-number=${BUILD_NUMBER} " +
-									'-Dmaven.test.skip=true clean deploy -U -B'
-						}
+					docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.basic']) {
+						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml -Pci,artifactory ' +
+								'-Dartifactory.server=https://repo.spring.io ' +
+								"-Dartifactory.username=${ARTIFACTORY_USR} " +
+								"-Dartifactory.password=${ARTIFACTORY_PSW} " +
+								"-Dartifactory.staging-repository=libs-snapshot-local " +
+								"-Dartifactory.build-name=spring-data-mongodb " +
+								"-Dartifactory.build-number=${BUILD_NUMBER} " +
+								'-Dmaven.test.skip=true clean deploy -U -B'
 					}
 				}
 			}

README.adoc

@@ -1,8 +1,8 @@
-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]
+image:https://spring.io/badges/spring-data-mongodb/ga.svg[Spring Data MongoDB,link=https://spring.io/projects/spring-data-mongodb#quick-start] image:https://spring.io/badges/spring-data-mongodb/snapshot.svg[Spring Data MongoDB,link=https://spring.io/projects/spring-data-mongodb#quick-start]
 
 = 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.
+The primary goal of the https://spring.io/projects/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.
 
 The Spring Data MongoDB project aims to provide a familiar and consistent Spring-based programming model for new datastores while retaining store-specific features and capabilities.
 The Spring Data MongoDB project provides integration with the MongoDB document database.
@@ -115,7 +115,7 @@ Use `<mongo:client-settings cluster-hosts="..." />` instead
 
 | `<mongo:db-factory writeConcern="..." />`
 | NONE, NORMAL, SAFE, FSYNC_SAFE, REPLICAS_SAFE, MAJORITY
-| W1, W2, W3, UNAKNOWLEDGED, AKNOWLEDGED, JOURNALED, MAJORITY
+| W1, W2, W3, UNACKNOWLEDGED, ACKNOWLEDGED, JOURNALED, MAJORITY
 |===
 
 .Removed XML Namespace Elements and Attributes:
@@ -271,7 +271,7 @@ The https://spring.io/[spring.io] site contains several guides that show how to
 [[building-from-source]]
 == Building from Source
 
-You do not need to build from source to use Spring Data. Binaries are available in https://repo.spring.io[repo.spring.io]
+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.
@@ -281,17 +281,16 @@ Follow this https://start.spring.io/#type=maven-project&language=java&platformVe
 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]).
+However, 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]
+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]
+In order to build Spring Data MongoDB, first 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`).
+your MongoDB installation (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 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:
 
@@ -332,7 +331,7 @@ In case you need to, you can adjust the `ulimit` with the following command (327
 $ ulimit -n 32768
 ----
 
-You can use `ulimit -a` again to verify the `ulimit` for "_open files_" was set appropriately.
+You can use `ulimit -a` again to verify the `ulimit` on "_open files_" was set appropriately.
 
 Now you are ready to build Spring Data MongoDB. Simply enter the following `mvnw` (Maven Wrapper) command:
 

ci/openjdk11-mongodb-4.4/Dockerfile

@@ -0,0 +1,22 @@
+ARG BASE
+FROM ${BASE}
+# Any ARG statements before FROM are cleared.
+ARG MONGODB
+
+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/ports.ubuntu.com/mirrors.ocf.berkeley.edu/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,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.4.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/openjdk17-mongodb-4.4/Dockerfile

@@ -7,15 +7,16 @@ 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; \
-	echo ${TZ} > /etc/timezone;
+	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/ports.ubuntu.com/mirrors.ocf.berkeley.edu/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,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.4.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=${MONGODB} ; \
-	apt-get clean; \
-	rm -rf /var/lib/apt/lists/*;
+RUN apt-get update && \
+	apt-get install -y mongodb-org=${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

@@ -7,17 +7,16 @@ 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 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;
+	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/ports.ubuntu.com/mirrors.ocf.berkeley.edu/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 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=${MONGODB} ; \
-	apt-get clean; \
-	rm -rf /var/lib/apt/lists/*;
+RUN apt-get update && \
+	apt-get install -y mongodb-org=${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

@@ -0,0 +1,24 @@
+ARG BASE
+FROM ${BASE}
+# Any ARG statements before FROM are cleared.
+ARG MONGODB
+
+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/ports.ubuntu.com/mirrors.ocf.berkeley.edu/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,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/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/openjdk8-mongodb-5.0/Dockerfile

@@ -0,0 +1,24 @@
+ARG BASE
+FROM ${BASE}
+# Any ARG statements before FROM are cleared.
+ARG MONGODB
+
+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/ports.ubuntu.com/mirrors.ocf.berkeley.edu/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,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/5.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-5.0.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/pipeline.properties

@@ -1,10 +1,15 @@
 # Java versions
-java.main.tag=17.0.2_8-jdk
+java.main.tag=8u345-b01-jdk-focal
+java.next.tag=11.0.16.1_1-jdk-focal
+java.lts.tag=17.0.4.1_1-jdk-focal
 
 # Docker container images - standard
 docker.java.main.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.main.tag}
+docker.java.next.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.next.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

@@ -5,17 +5,17 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>4.0.0-M2</version>
+	<version>3.3.11-SNAPSHOT</version>
 	<packaging>pom</packaging>
 
 	<name>Spring Data MongoDB</name>
 	<description>MongoDB support for Spring Data</description>
-	<url>https://projects.spring.io/spring-data-mongodb</url>
+	<url>https://spring.io/projects/spring-data-mongodb</url>
 
 	<parent>
 		<groupId>org.springframework.data.build</groupId>
 		<artifactId>spring-data-parent</artifactId>
-		<version>3.0.0-M2</version>
+		<version>2.6.11-SNAPSHOT</version>
 	</parent>
 
 	<modules>
@@ -24,11 +24,10 @@
 	</modules>
 
 	<properties>
-		<source.level>16</source.level>
 		<project.type>multi</project.type>
 		<dist.id>spring-data-mongodb</dist.id>
-		<springdata.commons>3.0.0-M2</springdata.commons>
-		<mongo>4.5.0</mongo>
+		<springdata.commons>2.6.11-SNAPSHOT</springdata.commons>
+		<mongo>4.4.2</mongo>
 		<mongo.reactivestreams>${mongo}</mongo.reactivestreams>
 		<jmh.version>1.19</jmh.version>
 	</properties>
@@ -113,6 +112,17 @@
 		</developer>
 	</developers>
 
+	<scm>
+		<connection>scm:git:https://github.com/spring-projects/spring-data-mongodb.git</connection>
+		<developerConnection>scm:git:git@github.com:spring-projects/spring-data-mongodb.git</developerConnection>
+		<url>https://github.com/spring-projects/spring-data-mongodb</url>
+	</scm>
+
+	<issueManagement>
+		<system>GitHub</system>
+		<url>https://github.com/spring-projects/spring-data-mongodb/issues</url>
+	</issueManagement>
+
 	<profiles>
 		<profile>
 			<id>benchmarks</id>
@@ -135,8 +145,8 @@
 
 	<repositories>
 		<repository>
-			<id>spring-libs-milestone</id>
-			<url>https://repo.spring.io/libs-milestone</url>
+			<id>spring-libs-snapshot</id>
+			<url>https://repo.spring.io/libs-snapshot</url>
 		</repository>
 		<repository>
 			<id>sonatype-libs-snapshot</id>

spring-data-mongodb-benchmarks/pom.xml

@@ -7,7 +7,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>4.0.0-M2</version>
+		<version>3.3.11-SNAPSHOT</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>4.0.0-M2</version>
+		<version>3.3.11-SNAPSHOT</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>4.0.0-M2</version>
+		<version>3.3.11-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
@@ -122,6 +122,27 @@
 			<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>
@@ -131,6 +152,12 @@
 
 		<!-- 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>
@@ -140,48 +167,31 @@
 		</dependency>
 
 		<dependency>
-			<groupId>jakarta.enterprise</groupId>
-			<artifactId>jakarta.enterprise.cdi-api</artifactId>
+			<groupId>javax.enterprise</groupId>
+			<artifactId>cdi-api</artifactId>
 			<version>${cdi}</version>
 			<scope>provided</scope>
 			<optional>true</optional>
 		</dependency>
 
 		<dependency>
-			<groupId>jakarta.annotation</groupId>
-			<artifactId>jakarta.annotation-api</artifactId>
-			<version>${jakarta-annotation-api}</version>
+			<groupId>javax.annotation</groupId>
+			<artifactId>javax.annotation-api</artifactId>
+			<version>${javax-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>jakarta.validation</groupId>
-			<artifactId>jakarta.validation-api</artifactId>
+			<groupId>javax.validation</groupId>
+			<artifactId>validation-api</artifactId>
 			<version>${validation}</version>
 			<optional>true</optional>
 		</dependency>
@@ -196,23 +206,28 @@
 		<dependency>
 			<groupId>org.hibernate</groupId>
 			<artifactId>hibernate-validator</artifactId>
-			<version>7.0.1.Final</version>
+			<version>5.4.3.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>
+			<groupId>org.glassfish</groupId>
+			<artifactId>javax.el</artifactId>
+			<version>3.0.1-b11</version>
+			<scope>test</scope>
 		</dependency>
 
 		<dependency>
-			<groupId>org.glassfish</groupId>
-			<artifactId>jakarta.el</artifactId>
-			<version>4.0.2</version>
-			<scope>provided</scope>
+			<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>
 			<optional>true</optional>
 		</dependency>
 
@@ -222,6 +237,13 @@
 			<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>
@@ -257,9 +279,9 @@
 		</dependency>
 
 		<dependency>
-			<groupId>jakarta.transaction</groupId>
-			<artifactId>jakarta.transaction-api</artifactId>
-			<version>2.0.0</version>
+			<groupId>javax.transaction</groupId>
+			<artifactId>jta</artifactId>
+			<version>1.1</version>
 			<scope>test</scope>
 		</dependency>
 

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

@@ -103,11 +103,19 @@ 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

@@ -193,11 +193,19 @@ 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) {
 
@@ -206,6 +214,10 @@ public class MongoDatabaseUtils {
 			}
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.transaction.support.ResourceHolderSynchronization#afterCompletion(int)
+		 */
 		@Override
 		public void afterCompletion(int status) {
 
@@ -216,6 +228,10 @@ 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

@@ -0,0 +1,57 @@
+/*
+ * 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

@@ -106,6 +106,10 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		this.options = options;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * org.springframework.transaction.support.AbstractPlatformTransactionManager#doGetTransaction()
+	 */
 	@Override
 	protected Object doGetTransaction() throws TransactionException {
 
@@ -114,11 +118,19 @@ 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 {
 
@@ -148,6 +160,10 @@ 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 {
 
@@ -157,11 +173,19 @@ 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 {
 
@@ -212,6 +236,10 @@ 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 {
 
@@ -231,6 +259,10 @@ 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 {
 
@@ -238,6 +270,10 @@ 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) {
 
@@ -289,11 +325,19 @@ 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();
@@ -461,11 +505,19 @@ 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

@@ -214,11 +214,19 @@ 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) {
 
@@ -229,6 +237,10 @@ public class ReactiveMongoDatabaseUtils {
 			return Mono.empty();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.transaction.reactive.ReactiveResourceSynchronization#afterCompletion(int)
+		 */
 		@Override
 		public Mono<Void> afterCompletion(int status) {
 
@@ -244,6 +256,10 @@ 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

@@ -110,6 +110,10 @@ 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 {
@@ -119,11 +123,19 @@ 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 {
@@ -163,6 +175,10 @@ 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 {
@@ -176,6 +192,10 @@ 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) {
@@ -183,6 +203,10 @@ 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 {
@@ -219,6 +243,10 @@ 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) {
@@ -240,6 +268,10 @@ 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 {
@@ -250,6 +282,10 @@ 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) {
@@ -304,6 +340,10 @@ public class ReactiveMongoTransactionManager extends AbstractReactiveTransaction
 		return databaseFactory;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
+	 */
 	@Override
 	public void afterPropertiesSet() {
 		getRequiredDatabaseFactory();
@@ -469,11 +509,19 @@ 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

@@ -95,6 +95,10 @@ 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.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 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 Log LOGGER = LogFactory.getLog(SpringDataMongoDB.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(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(String.format("Cannot read Spring Data MongoDB version '%s'.", versionString));
+			LOGGER.debug("Cannot read Spring Data MongoDB version '{}'.", versionString);
 		}
 
 		return FALLBACK_VERSION;

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

@@ -25,7 +25,9 @@ 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;
@@ -78,6 +80,24 @@ 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

@@ -30,6 +30,10 @@ 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

@@ -34,6 +34,10 @@ 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 {
@@ -42,6 +46,10 @@ 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

@@ -24,7 +24,6 @@ import java.util.List;
 import java.util.Set;
 
 import org.springframework.beans.BeanMetadataElement;
-import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
@@ -64,6 +63,7 @@ import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.util.xml.DomUtils;
+
 import org.w3c.dom.Element;
 
 /**
@@ -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("jakarta.validation.Validator",
+	private static final boolean JSR_303_PRESENT = ClassUtils.isPresent("javax.validation.Validator",
 			MappingMongoConverterParser.class.getClassLoader());
 
 	/* (non-Javadoc)
@@ -135,9 +135,7 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 					new BeanComponentDefinition(indexOperationsProviderBuilder.getBeanDefinition(), "indexOperationsProvider"));
 		}
 
-		try {
-			registry.getBeanDefinition(INDEX_HELPER_BEAN_NAME);
-		} catch (NoSuchBeanDefinitionException ignored) {
+		if (!registry.containsBeanDefinition(INDEX_HELPER_BEAN_NAME)) {
 
 			BeanDefinitionBuilder indexHelperBuilder = BeanDefinitionBuilder
 					.genericBeanDefinition(MongoPersistentEntityIndexCreator.class);
@@ -151,7 +149,7 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 
 		BeanDefinition validatingMongoEventListener = potentiallyCreateValidatingMongoEventListener(element, parserContext);
 
-		if (validatingMongoEventListener != null) {
+		if (validatingMongoEventListener != null && !registry.containsBeanDefinition(VALIDATING_EVENT_LISTENER_BEAN_NAME)) {
 			parserContext.registerBeanComponent(
 					new BeanComponentDefinition(validatingMongoEventListener, VALIDATING_EVENT_LISTENER_BEAN_NAME));
 		}
@@ -165,15 +163,16 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 	private BeanDefinition potentiallyCreateValidatingMongoEventListener(Element element, ParserContext parserContext) {
 
 		String disableValidation = element.getAttribute("disable-validation");
-		boolean validationDisabled = StringUtils.hasText(disableValidation) && Boolean.valueOf(disableValidation);
+		boolean validationDisabled = StringUtils.hasText(disableValidation) && Boolean.parseBoolean(disableValidation);
 
 		if (!validationDisabled) {
 
 			BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition();
-			RuntimeBeanReference validator = getValidator(builder, parserContext);
+			RuntimeBeanReference validator = getValidator(element, parserContext);
 
 			if (validator != null) {
 				builder.getRawBeanDefinition().setBeanClass(ValidatingMongoEventListener.class);
+				builder.getRawBeanDefinition().setSource(element);
 				builder.addConstructorArgValue(validator);
 
 				return builder.getBeanDefinition();
@@ -195,7 +194,6 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		validatorDef.setSource(source);
 		validatorDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
 		String validatorName = parserContext.getReaderContext().registerWithGeneratedName(validatorDef);
-		parserContext.registerBeanComponent(new BeanComponentDefinition(validatorDef, validatorName));
 
 		return new RuntimeBeanReference(validatorName);
 	}
@@ -376,6 +374,10 @@ 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

@@ -47,16 +47,28 @@ 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

@@ -18,7 +18,6 @@ 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;
@@ -28,8 +27,6 @@ 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;
 
@@ -42,16 +39,28 @@ 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) {
 
@@ -61,6 +70,10 @@ 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) {
 
@@ -68,13 +81,17 @@ class MongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 
 		BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(IsNewAwareAuditingHandler.class);
 
-		BeanDefinitionBuilder definition = BeanDefinitionBuilder.genericBeanDefinition(org.springframework.data.repository.config.PersistentEntitiesFactoryBean.class);
-		definition.addConstructorArgValue(new RuntimeBeanReference(MappingContext.class));
+		BeanDefinitionBuilder definition = BeanDefinitionBuilder.genericBeanDefinition(PersistentEntitiesFactoryBean.class);
+		definition.setAutowireMode(AbstractBeanDefinition.AUTOWIRE_CONSTRUCTOR);
 
 		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

@@ -35,6 +35,10 @@ 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

@@ -51,6 +51,10 @@ 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

@@ -62,6 +62,10 @@ 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 {
@@ -70,6 +74,10 @@ 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

@@ -26,6 +26,10 @@ 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

@@ -40,6 +40,7 @@ import org.w3c.dom.Element;
  * @author Christoph Strobl
  * @author Mark Paluch
  */
+@SuppressWarnings("deprecation")
 abstract class MongoParsingUtils {
 
 	private MongoParsingUtils() {}

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

@@ -39,6 +39,10 @@ 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 {
@@ -47,6 +51,10 @@ 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

@@ -41,11 +41,19 @@ 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

@@ -38,16 +38,28 @@ 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) {
 
@@ -62,6 +74,10 @@ 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

@@ -32,6 +32,10 @@ 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

@@ -29,6 +29,10 @@ 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.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -43,9 +43,13 @@ 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 %s '%s'. Check your replica set configuration!";
-	private static final Log LOG = LogFactory.getLog(ServerAddressPropertyEditor.class);
+	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);
 
+	/*
+	 * (non-Javadoc)
+	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
+	 */
 	@Override
 	public void setAsText(@Nullable String replicaSetString) {
 
@@ -84,18 +88,14 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 	private ServerAddress parseServerAddress(String source) {
 
 		if (!StringUtils.hasText(source)) {
-			if(LOG.isWarnEnabled()) {
-				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source));
-			}
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
 			return null;
 		}
 
 		String[] hostAndPort = extractHostAddressAndPort(source.trim());
 
 		if (hostAndPort.length > 2) {
-			if(LOG.isWarnEnabled()) {
-				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source));
-			}
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
 			return null;
 		}
 
@@ -105,13 +105,9 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 
 			return port == null ? new ServerAddress(hostAddress) : new ServerAddress(hostAddress, port);
 		} catch (UnknownHostException e) {
-			if(LOG.isWarnEnabled()) {
-				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "host", hostAndPort[0]));
-			}
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "host", hostAndPort[0]);
 		} catch (NumberFormatException e) {
-			if(LOG.isWarnEnabled()) {
-				LOG.warn(String.format(COULD_NOT_PARSE_ADDRESS_MESSAGE, "port", hostAndPort[1]));
-			}
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "port", hostAndPort[1]);
 		}
 
 		return null;

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

@@ -26,6 +26,10 @@ 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

@@ -29,6 +29,10 @@ 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

@@ -189,6 +189,10 @@ 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

@@ -47,6 +47,20 @@ public class CollectionOptions {
 	private ValidationOptions validationOptions;
 	private @Nullable TimeSeriesOptions timeSeriesOptions;
 
+	/**
+	 * 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(), null);
+	}
+
 	private CollectionOptions(@Nullable Long size, @Nullable Long maxDocuments, @Nullable Boolean capped,
 			@Nullable Collation collation, ValidationOptions validationOptions,
 			@Nullable TimeSeriesOptions timeSeriesOptions) {

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

@@ -176,16 +176,20 @@ class CountQuery {
 		Document $geoWithinMin = new Document("$geoWithin",
 				new Document(spheric ? "$centerSphere" : "$center", $centerMin));
 
-		List<Document> criteria = new ArrayList<>();
+		List<Document> criteria;
 
 		if ($and != null) {
 			if ($and instanceof Collection) {
-				criteria.addAll((Collection) $and);
+				Collection andElements = (Collection) $and;
+				criteria = new ArrayList<>(andElements.size() + 2);
+				criteria.addAll(andElements);
 			} else {
 				throw new IllegalArgumentException(
 						"Cannot rewrite query as it contains an '$and' element that is not a Collection!: Offending element: "
 								+ $and);
 			}
+		} else {
+			criteria = new ArrayList<>(2);
 		}
 
 		criteria.add(new Document("$nor", Collections.singletonList(new Document(key, $geoWithinMin))));

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

@@ -109,6 +109,10 @@ 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) {
 
@@ -121,6 +125,10 @@ 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) {
 
@@ -131,6 +139,10 @@ 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) {
@@ -141,6 +153,10 @@ 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) {
 
@@ -153,6 +169,10 @@ 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) {
@@ -163,6 +183,10 @@ 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) {
 
@@ -175,11 +199,19 @@ 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) {
 
@@ -190,6 +222,10 @@ 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) {
 
@@ -203,6 +239,10 @@ 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) {
 
@@ -215,6 +255,10 @@ 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) {
 
@@ -234,6 +278,10 @@ 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

@@ -112,6 +112,10 @@ 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 -> {
@@ -146,6 +150,10 @@ 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 -> {
@@ -155,10 +163,18 @@ 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>>() {
@@ -172,7 +188,8 @@ public class DefaultIndexOperations implements IndexOperations {
 
 			private List<IndexInfo> getIndexData(MongoCursor<Document> cursor) {
 
-				List<IndexInfo> indexInfoList = new ArrayList<>();
+				int available = cursor.available();
+				List<IndexInfo> indexInfoList = available > 0 ? new ArrayList<>(available) : new ArrayList<>();
 
 				while (cursor.hasNext()) {
 

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

@@ -42,6 +42,10 @@ 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

@@ -86,6 +86,10 @@ 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 -> {
@@ -115,14 +119,26 @@ 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

@@ -70,11 +70,19 @@ 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) {
 
@@ -84,6 +92,10 @@ 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) {
 
@@ -103,6 +115,10 @@ 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) {
 
@@ -119,6 +135,10 @@ class DefaultScriptOperations implements ScriptOperations {
 		});
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.ScriptOperations#exists(java.lang.String)
+	 */
 	@Override
 	public boolean exists(String scriptName) {
 
@@ -127,6 +147,10 @@ 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/EntityOperations.java

@@ -21,10 +21,8 @@ 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;
@@ -32,10 +30,7 @@ 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;
@@ -44,11 +39,6 @@ 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;
@@ -57,10 +47,6 @@ 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.
  *
@@ -76,31 +62,9 @@ class EntityOperations {
 	private static final String ID_FIELD = "_id";
 
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context;
-	private final QueryMapper queryMapper;
 
-	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) {
+	EntityOperations(MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context) {
 		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);
 	}
 
 	/**
@@ -174,7 +138,14 @@ class EntityOperations {
 					"No class parameter provided, entity collection can't be determined!");
 		}
 
-		return context.getRequiredPersistentEntity(entityClass).getCollection();
+		MongoPersistentEntity<?> persistentEntity = context.getPersistentEntity(entityClass);
+
+		if (persistentEntity == null) {
+			throw new MappingException(String.format(
+					"Cannot determine collection name from type '%s'. Is it a store native type?", entityClass.getName()));
+		}
+
+		return persistentEntity.getCollection();
 	}
 
 	public Query getByIdInQuery(Collection<?> entities) {
@@ -265,89 +236,6 @@ 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.
 	 *
@@ -492,21 +380,37 @@ 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) {
@@ -516,11 +420,19 @@ 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 //
@@ -528,27 +440,47 @@ 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;
@@ -561,6 +493,10 @@ 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) {
@@ -600,16 +536,28 @@ 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() {
 
@@ -622,6 +570,10 @@ 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() {
 
@@ -632,6 +584,10 @@ 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) {
 
@@ -647,6 +603,10 @@ class EntityOperations {
 			return MappedDocument.of(document);
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.EntityOperations.Entity#assertUpdateableIdIfNotSet()
+		 */
 		public void assertUpdateableIdIfNotSet() {
 
 			if (!entity.hasIdProperty()) {
@@ -667,22 +627,38 @@ 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());
@@ -717,6 +693,10 @@ 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) {
@@ -738,6 +718,10 @@ class EntityOperations {
 			return propertyAccessor.getBean();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.EntityOperations.MappedEntity#getVersion()
+		 */
 		@Override
 		@Nullable
 		public Number getVersion() {
@@ -747,6 +731,10 @@ class EntityOperations {
 			return propertyAccessor.getProperty(versionProperty, Number.class);
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity#initializeVersionProperty()
+		 */
 		@Override
 		public T initializeVersionProperty() {
 
@@ -761,6 +749,10 @@ class EntityOperations {
 			return propertyAccessor.getBean();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity#incrementVersion()
+		 */
 		@Override
 		public T incrementVersion() {
 
@@ -832,11 +824,19 @@ 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) {
 
@@ -871,11 +871,19 @@ 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) {
 

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

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

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

@@ -15,11 +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.mongodb.core.aggregation.TypedAggregation;
+import org.springframework.data.util.CloseableIterator;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -38,6 +37,10 @@ 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) {
 
@@ -66,6 +69,10 @@ 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) {
 
@@ -74,6 +81,10 @@ 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) {
 
@@ -82,13 +93,21 @@ 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 Stream<T> stream() {
+		public CloseableIterator<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 the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-		 *         through a try-with-resources clause).
+		 * @return a {@link Stream} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed. Never
+		 *         {@literal null}.
 		 */
 		Stream<T> stream();
 

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

@@ -20,11 +20,12 @@ 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;
@@ -50,6 +51,10 @@ 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) {
 
@@ -69,11 +74,11 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 		private final MongoTemplate template;
 		private final Class<?> domainType;
 		private final Class<T> returnType;
-		private final @Nullable String collection;
+		@Nullable private final String collection;
 		private final Query query;
 
 		ExecutableFindSupport(MongoTemplate template, Class<?> domainType, Class<T> returnType,
-				@Nullable String collection, Query query) {
+				String collection, Query query) {
 			this.template = template;
 			this.domainType = domainType;
 			this.returnType = returnType;
@@ -81,6 +86,10 @@ 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) {
 
@@ -89,6 +98,10 @@ 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) {
 
@@ -97,6 +110,10 @@ 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) {
 
@@ -105,6 +122,10 @@ 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() {
 
@@ -121,6 +142,10 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 			return result.iterator().next();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.ExecutableFindOperation.TerminatingFind#firstValue()
+		 */
 		@Override
 		public T firstValue() {
 
@@ -129,31 +154,55 @@ 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 doStream();
+			return StreamUtils.createStreamFromIterator(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) {
@@ -178,7 +227,7 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 					returnType == domainType ? (Class<T>) Object.class : returnType);
 		}
 
-		private Stream<T> doStream() {
+		private CloseableIterator<T> doStream() {
 			return template.doStream(query, domainType, getCollectionName(), returnType);
 		}
 
@@ -208,6 +257,10 @@ 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) {
 
@@ -242,6 +295,10 @@ 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) {
@@ -251,6 +308,10 @@ 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) {
 
@@ -259,6 +320,10 @@ 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

@@ -40,6 +40,10 @@ 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) {
 
@@ -67,6 +71,10 @@ 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) {
 
@@ -75,6 +83,10 @@ 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) {
 
@@ -83,6 +95,10 @@ 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) {
 
@@ -92,6 +108,10 @@ 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) {
 
@@ -100,6 +120,10 @@ 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

@@ -41,6 +41,10 @@ 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) {
 
@@ -67,6 +71,10 @@ 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) {
 
@@ -75,6 +83,10 @@ 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) {
 
@@ -83,16 +95,28 @@ 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

@@ -40,6 +40,10 @@ 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) {
 
@@ -81,6 +85,10 @@ 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) {
 
@@ -90,6 +98,10 @@ 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) {
 
@@ -99,6 +111,10 @@ 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) {
 
@@ -108,6 +124,10 @@ 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) {
 
@@ -117,6 +137,10 @@ 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) {
 
@@ -126,6 +150,10 @@ 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) {
 
@@ -135,6 +163,10 @@ 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) {
 
@@ -144,21 +176,37 @@ 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() {
 
@@ -167,6 +215,10 @@ 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/MappedDocument.java

@@ -112,31 +112,55 @@ 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

@@ -24,6 +24,7 @@ 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;
@@ -44,7 +45,6 @@ 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;
 
@@ -62,7 +62,6 @@ 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}.
@@ -73,48 +72,29 @@ class MappingMongoJsonSchemaCreator implements MongoJsonSchemaCreator {
 	MappingMongoJsonSchemaCreator(MongoConverter converter) {
 
 		this(converter, (MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty>) converter.getMappingContext(),
-				(property) -> true, new LinkedMultiValueMap<>());
+				(property) -> true);
 	}
 
 	@SuppressWarnings("unchecked")
 	MappingMongoJsonSchemaCreator(MongoConverter converter,
 			MappingContext<MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext,
-			Predicate<JsonSchemaPropertyContext> filter, LinkedMultiValueMap<String, Class<?>> mergeProperties) {
+			Predicate<JsonSchemaPropertyContext> filter) {
 
 		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);
+		return new MappingMongoJsonSchemaCreator(converter, mappingContext, filter);
 	}
 
-	@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
+	/*
+	 * (non-Javadoc)
+	 * org.springframework.data.mongodb.core.MongoJsonSchemaCreator#createSchemaFor(java.lang.Class)
 	 */
-	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) {
 
@@ -155,12 +135,9 @@ 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 (!filter.test(new PropertyContext(
+					currentPath.stream().map(PersistentProperty::getName).collect(Collectors.joining(".")), nested))) {
+				continue;
 			}
 
 			if (path.contains(nested)) { // cycle guard
@@ -178,34 +155,14 @@ 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 (!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);
-			}
+		if (!isCollection(property) && property.isEntity() && ObjectUtils.nullSafeEquals(rawTargetType, targetType)) {
+			return createObjectSchemaPropertyForEntity(path, property, required);
 		}
 
 		String fieldName = computePropertyFieldName(property);

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

@@ -46,16 +46,25 @@ 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

@@ -119,15 +119,27 @@ 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());
@@ -324,6 +336,10 @@ 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 {
 
@@ -337,11 +353,6 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 	}
 
 	private String getOrDefault(Object value, String defaultValue) {
-
-		if(value == null) {
-			return defaultValue;
-		}
-		String sValue = value.toString();
-		return StringUtils.hasText(sValue) ? sValue : defaultValue;
+		return !StringUtils.isEmpty(value) ? value.toString() : defaultValue;
 	}
 }

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

@@ -84,10 +84,18 @@ 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 {
 
@@ -110,16 +118,28 @@ 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);
 	}
@@ -160,31 +180,55 @@ 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

@@ -0,0 +1,50 @@
+/*
+ * 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

@@ -88,6 +88,10 @@ public class MongoEncryptionSettingsFactoryBean implements FactoryBean<AutoEncry
 		this.schemaMap = schemaMap;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see  org.springframework.beans.factory.FactoryBean#getObject()
+	 */
 	@Override
 	public AutoEncryptionSettings getObject() {
 
@@ -105,6 +109,10 @@ 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

@@ -68,6 +68,10 @@ 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 +15,6 @@
  */
 package org.springframework.data.mongodb.core;
 
-import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.function.Predicate;
@@ -63,6 +62,7 @@ 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
@@ -78,20 +78,6 @@ 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}.
 	 *
@@ -101,39 +87,30 @@ public interface MongoJsonSchemaCreator {
 	 */
 	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
@@ -232,19 +209,4 @@ public interface MongoJsonSchemaCreator {
 
 		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

@@ -20,7 +20,6 @@ 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;
@@ -33,6 +32,8 @@ 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;
@@ -41,6 +42,7 @@ 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;
@@ -55,7 +57,8 @@ 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>.
@@ -77,11 +80,12 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *
 	 * @param entityClass must not be {@literal null}.
 	 * @return never {@literal null}.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be derived from the type.
 	 */
 	String getCollectionName(Class<?> entityClass);
 
 	/**
-	 * Execute a MongoDB command expressed as a JSON string. Parsing is delegated to {@link Document#parse(String)} to
+	 * Execute the 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.
 	 *
@@ -121,7 +125,8 @@ 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
@@ -133,7 +138,8 @@ 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}.
@@ -145,7 +151,8 @@ 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
@@ -169,7 +176,8 @@ 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}.
 	 *
@@ -204,7 +212,8 @@ 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}.
@@ -217,34 +226,34 @@ 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 String} that wraps the Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
+	 * Returns a {@link CloseableIterator} that wraps the a 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 the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return will never be {@literal null}.
 	 * @since 1.7
 	 */
-	<T> Stream<T> stream(Query query, Class<T> entityType);
+	<T> CloseableIterator<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 Stream} that wraps the Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
+	 * Returns a {@link CloseableIterator} that wraps the a 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 the result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return will never be {@literal null}.
 	 * @since 1.10
 	 */
-	<T> Stream<T> stream(Query query, Class<T> entityType, String collectionName);
+	<T> CloseableIterator<T> stream(Query query, Class<T> entityType, String collectionName);
 
 	/**
 	 * Create an uncapped collection with a name based on the provided entity class.
@@ -291,7 +300,8 @@ 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}.
@@ -300,7 +310,8 @@ 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}.
@@ -309,7 +320,8 @@ 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}.
@@ -318,7 +330,8 @@ 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}.
@@ -326,7 +339,8 @@ 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.
@@ -389,9 +403,11 @@ 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.
 	 *
@@ -401,9 +417,11 @@ 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.
 	 *
@@ -413,6 +431,43 @@ 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.
@@ -467,9 +522,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <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. The name of the inputCollection is derived from
-	 * the inputType of the aggregation.
+	 * 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.
 	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -478,37 +533,35 @@ 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 result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return The results of the aggregation operation.
 	 * @since 2.0
 	 */
-	<O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
+	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <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>
+	 * <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 />
 	 * 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 result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return The results of the aggregation operation.
 	 * @since 2.0
 	 */
-	<O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType);
+	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <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>
+	 * <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 />
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
 	 *
@@ -517,18 +570,17 @@ 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 result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return The results of the aggregation operation.
 	 * @since 2.0
 	 */
-	<O> Stream<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
+	<O> CloseableIterator<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
 
 	/**
 	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
-	 * <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>
+	 * <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 />
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
 	 *
@@ -537,11 +589,10 @@ 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 result {@link Stream}, containing mapped objects, needing to be closed once fully processed (e.g.
-	 *         through a try-with-resources clause).
+	 * @return The results of the aggregation operation.
 	 * @since 2.0
 	 */
-	<O> Stream<O> aggregateStream(Aggregation aggregation, String collectionName, Class<O> outputType);
+	<O> CloseableIterator<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
@@ -551,9 +602,7 @@ 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);
 
@@ -566,9 +615,7 @@ 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);
 
@@ -582,9 +629,7 @@ 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);
 
@@ -598,9 +643,7 @@ 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);
 
@@ -659,9 +702,11 @@ 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}.
 	 *
@@ -675,9 +720,11 @@ 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}.
 	 *
@@ -721,9 +768,11 @@ 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}.
 	 *
@@ -735,9 +784,11 @@ 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}.
 	 *
@@ -918,6 +969,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          fields specification. Must not be {@literal null}.
 	 * @param replacement the replacement document. Must not be {@literal null}.
 	 * @return the converted object that was updated or {@literal null}, if not found.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	@Nullable
@@ -959,6 +1012,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @return the converted object that was updated or {@literal null}, if not found. Depending on the value of
 	 *         {@link FindAndReplaceOptions#isReturnNew()} this will either be the object as it was before the update or
 	 *         as it is after the update.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	@Nullable
@@ -1032,6 +1087,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @return the converted object that was updated or {@literal null}, if not found. Depending on the value of
 	 *         {@link FindAndReplaceOptions#isReturnNew()} this will either be the object as it was before the update or
 	 *         as it is after the update.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	@Nullable
@@ -1069,8 +1126,10 @@ 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}.
 	 *
@@ -1087,7 +1146,8 @@ 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}.
 	 *
@@ -1106,96 +1166,8 @@ 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 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 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);
-
-	/**
-	 * 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 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.
-	 * @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 />
-	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
-	 * transactions.
-	 *
-	 * @param entityClass must not be {@literal null}.
-	 * @return the estimated number of documents.
-	 * @since 3.1
-	 */
-	default long estimatedCount(Class<?> entityClass) {
-
-		Assert.notNull(entityClass, "Entity class must not be null!");
-		return estimatedCount(getCollectionName(entityClass));
-	}
-
-	/**
-	 * 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.
-	 *
-	 * @param collectionName must not be {@literal null}.
-	 * @return the estimated number of documents.
-	 * @since 3.1
-	 */
-	long estimatedCount(String collectionName);
-
-	/**
-	 * Returns the number of documents for the given {@link Query} by querying the collection of the given entity class.
+	 * count all matches.
 	 * <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
@@ -1206,11 +1178,10 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          {@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
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 * 	  {@link #getCollectionName(Class) derived} from the given type.
 	 */
-	default long exactCount(Query query, Class<?> entityClass) {
-		return exactCount(query, entityClass, getCollectionName(entityClass));
-	}
+	long count(Query query, Class<?> entityClass);
 
 	/**
 	 * Returns the number of documents for the given {@link Query} querying the given collection. The given {@link Query}
@@ -1219,7 +1190,8 @@ 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 />
+	 * 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
@@ -1230,19 +1202,48 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @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);
+	long count(Query query, String collectionName);
+
+	/**
+	 * Estimate the number of documents, in the collection {@link #getCollectionName(Class) identified by the given type},
+	 * based on collection statistics.
+	 * <br />
+	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
+	 * transactions.
+	 *
+	 * @param entityClass must not be {@literal null}.
+	 * @return the estimated number of documents.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
+	 * @since 3.1
+	 */
+	default long estimatedCount(Class<?> entityClass) {
+
+		Assert.notNull(entityClass, "Entity class must not be null!");
+		return estimatedCount(getCollectionName(entityClass));
 	}
 
+	/**
+	 * 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.
+	 *
+	 * @param collectionName must not be {@literal null}.
+	 * @return the estimated number of documents.
+	 * @since 3.1
+	 */
+	long estimatedCount(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 />
+	 * 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
@@ -1254,18 +1255,20 @@ 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 exactCount(Query query, @Nullable Class<?> entityClass, String collectionName);
+	long count(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.
@@ -1273,13 +1276,17 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
 	 * @return the inserted object.
 	 * @throws IllegalArgumentException in case the {@code objectToSave} is collection-like.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	<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.
@@ -1297,6 +1304,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param batchToSave the batch of objects to save. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the inserted objects that.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	<T> Collection<T> insert(Collection<? extends T> batchToSave, Class<?> entityClass);
 
@@ -1315,37 +1324,46 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *
 	 * @param objectsToSave the list of objects to save. Must not be {@literal null}.
 	 * @return the inserted objects.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} for the given objects.
 	 */
 	<T> Collection<T> insertAll(Collection<? extends T> objectsToSave);
 
 	/**
 	 * 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}.
 	 * @return the saved object.
 	 * @throws IllegalArgumentException in case the {@code objectToSave} is collection-like.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	<T> T save(T objectToSave);
 
 	/**
 	 * 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}.
@@ -1367,9 +1385,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          the existing object. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
-	 * @since 3.0
 	 * @see Update
 	 * @see AggregationUpdate
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
+	 * @since 3.0
 	 */
 	UpdateResult upsert(Query query, UpdateDefinition update, Class<?> entityClass);
 
@@ -1421,9 +1441,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          the existing. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
-	 * @since 3.0
 	 * @see Update
 	 * @see AggregationUpdate
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
+	 * @since 3.0
 	 */
 	UpdateResult updateFirst(Query query, UpdateDefinition update, Class<?> entityClass);
 
@@ -1475,9 +1497,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *          the existing. Must not be {@literal null}.
 	 * @param entityClass class of the pojo to be operated on. Must not be {@literal null}.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
-	 * @since 3.0
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 * @see Update
 	 * @see AggregationUpdate
+	 * @since 3.0
 	 */
 	UpdateResult updateMulti(Query query, UpdateDefinition update, Class<?> entityClass);
 
@@ -1525,6 +1549,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 *
 	 * @param object must not be {@literal null}.
 	 * @return the {@link DeleteResult} which lets you access the results of the previous delete.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	DeleteResult remove(Object object);
 
@@ -1548,6 +1574,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param entityClass class that determines the collection to use.
 	 * @return the {@link DeleteResult} which lets you access the results of the previous delete.
 	 * @throws IllegalArgumentException when {@literal query} or {@literal entityClass} is {@literal null}.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	DeleteResult remove(Query query, Class<?> entityClass);
 
@@ -1595,6 +1623,8 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * @param query the query document that specifies the criteria used to find and remove documents.
 	 * @param entityClass class of the pojo to be operated on.
 	 * @return the {@link List} converted objects deleted by this operation.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 * @since 1.5
 	 */
 	<T> List<T> findAllAndRemove(Query query, Class<T> entityClass);

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

@@ -16,19 +16,18 @@
 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.mongodb.core.mapping.PersistentPropertyTranslator;
-import org.springframework.data.projection.EntityProjection;
-import org.springframework.data.util.Predicates;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.ProjectionInformation;
+import org.springframework.util.ClassUtils;
 
 /**
  * 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 {
@@ -41,37 +40,37 @@ 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 EntityProjection} is a {@literal DTO projection} or a
+	 * creating the projection (target) type if the {@code targetType} is a {@literal DTO projection} or a
 	 * {@literal closed interface projection}.
 	 *
-	 * @param projection must not be {@literal null}.
+	 * @param projectionFactory 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 computeMappedFieldsForProjection(EntityProjection<?, ?> projection,
-			Document fields) {
+	Document computeFieldsForProjection(ProjectionFactory projectionFactory, Document fields, Class<?> domainType,
+			Class<?> targetType) {
 
-		if (!projection.isClosedProjection()) {
+		if (!fields.isEmpty() || ClassUtils.isAssignable(domainType, targetType)) {
 			return fields;
 		}
 
 		Document projectedFields = new Document();
 
-		if (projection.getMappedType().getType().isInterface()) {
-			projection.forEach(it -> {
-				projectedFields.put(it.getPropertyPath().getSegment(), 1);
-			});
+		if (targetType.isInterface()) {
+
+			ProjectionInformation projectionInformation = projectionFactory.getProjectionInformation(targetType);
+
+			if (projectionInformation.isClosed()) {
+				projectionInformation.getInputProperties().forEach(it -> projectedFields.append(it.getName(), 1));
+			}
 		} else {
 
-			// 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);
+			MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(targetType);
+			if (entity != null) {
+				entity.doWithProperties(
+						(SimplePropertyHandler) persistentProperty -> projectedFields.append(persistentProperty.getName(), 1));
 			}
 		}
 

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

@@ -28,7 +28,6 @@ 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;
@@ -55,10 +54,11 @@ 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.EntityProjection;
+import org.springframework.data.projection.ProjectionFactory;
 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;
@@ -288,59 +288,45 @@ class QueryOperations {
 			return queryMapper.getMappedObject(getQueryObject(), entity);
 		}
 
-		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity,
-				EntityProjection<?, ?> projection) {
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType,
+				ProjectionFactory projectionFactory) {
 
-			Document fields = evaluateFields(entity);
+			Document fields = new Document();
 
-			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()) {
+			for (Entry<String, Object> entry : query.getFieldsObject().entrySet()) {
 
 				if (entry.getValue() instanceof MongoExpression) {
 
 					AggregationOperationContext ctx = entity == null ? Aggregation.DEFAULT_CONTEXT
 							: new RelaxedTypeBasedAggregationOperationContext(entity.getType(), mappingContext, queryMapper);
 
-					evaluated.put(entry.getKey(), AggregationExpression.from((MongoExpression) entry.getValue()).toDocument(ctx));
+					fields.put(entry.getKey(), AggregationExpression.from((MongoExpression) entry.getValue()).toDocument(ctx));
 				} else {
-					evaluated.put(entry.getKey(), entry.getValue());
+					fields.put(entry.getKey(), entry.getValue());
 				}
 			}
 
-			return evaluated;
+			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;
 		}
 
 		/**
@@ -402,8 +388,8 @@ class QueryOperations {
 		}
 
 		@Override
-		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity,
-				EntityProjection<?, ?> projection) {
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType,
+				ProjectionFactory projectionFactory) {
 			return getMappedFields(entity);
 		}
 

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

@@ -46,6 +46,10 @@ 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) {
 
@@ -71,6 +75,10 @@ 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) {
 
@@ -79,6 +87,10 @@ 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) {
 
@@ -87,6 +99,10 @@ 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

@@ -46,6 +46,10 @@ 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) {
 
@@ -72,6 +76,10 @@ 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) {
 
@@ -80,6 +88,10 @@ 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) {
 
@@ -88,6 +100,10 @@ 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) {
 
@@ -101,6 +117,10 @@ 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) {
 
@@ -109,6 +129,10 @@ 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) {
 
@@ -117,6 +141,10 @@ 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) {
 
@@ -126,6 +154,10 @@ 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) {
 
@@ -134,11 +166,19 @@ 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) {
 
@@ -148,6 +188,10 @@ 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

@@ -44,6 +44,10 @@ 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) {
 
@@ -77,6 +81,10 @@ 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) {
 
@@ -85,6 +93,10 @@ 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) {
 
@@ -93,6 +105,10 @@ 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) {
 
@@ -101,6 +117,10 @@ 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() {
 
@@ -110,6 +130,10 @@ class ReactiveFindOperationSupport implements ReactiveFindOperation {
 			return result.next();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.ReactiveFindOperation.TerminatingFind#one()
+		 */
 		@Override
 		public Mono<T> one() {
 
@@ -131,31 +155,55 @@ 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) {
 
@@ -207,6 +255,10 @@ 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) {
 
@@ -215,6 +267,10 @@ 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) {
@@ -224,6 +280,10 @@ 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

@@ -38,6 +38,10 @@ 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) {
 
@@ -59,6 +63,10 @@ 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) {
 
@@ -67,6 +75,10 @@ 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) {
 
@@ -75,6 +87,10 @@ 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/ReactiveMongoClientSettingsFactoryBean.java

@@ -0,0 +1,31 @@
+/*
+ * 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.
+ * 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.MongoClientSettings;
+
+/**
+ * A factory bean for construction of a {@link MongoClientSettings} instance to be used with the async MongoDB driver.
+ *
+ * @author Mark Paluch
+ * @author Christoph Strobl
+ * @since 2.0
+ * @deprecated since 3.0 - Use {@link MongoClientSettingsFactoryBean} instead.
+ */
+@Deprecated
+public class ReactiveMongoClientSettingsFactoryBean extends MongoClientSettingsFactoryBean {
+
+}

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

@@ -42,6 +42,7 @@ 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;
 
@@ -57,7 +58,8 @@ 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>.
@@ -89,7 +91,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	ReactiveIndexOperations indexOps(Class<?> entityClass);
 
 	/**
-	 * Execute a MongoDB command expressed as a JSON string. This will call the method JSON.parse that is part of the
+	 * Execute the 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.
 	 *
@@ -118,7 +120,8 @@ 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
@@ -129,7 +132,8 @@ 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}.
@@ -140,7 +144,8 @@ 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
@@ -153,7 +158,8 @@ 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.
@@ -171,7 +177,8 @@ 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.
@@ -197,14 +204,48 @@ 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.
 	 *
@@ -251,7 +292,8 @@ 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.
@@ -260,7 +302,8 @@ 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}.
@@ -269,7 +312,8 @@ 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}.
@@ -278,7 +322,8 @@ 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}.
@@ -286,7 +331,8 @@ 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.
@@ -294,9 +340,11 @@ 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.
 	 *
@@ -306,9 +354,11 @@ 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.
 	 *
@@ -320,9 +370,11 @@ 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}.
 	 *
@@ -335,9 +387,11 @@ 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}.
 	 *
@@ -383,7 +437,8 @@ 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}.
 	 *
@@ -395,9 +450,11 @@ 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}.
 	 *
@@ -508,9 +565,11 @@ 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}.
@@ -524,9 +583,11 @@ 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}.
@@ -542,8 +603,10 @@ 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}.
@@ -693,6 +756,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *          fields specification. Must not be {@literal null}.
 	 * @param replacement the replacement document. Must not be {@literal null}.
 	 * @return the converted object that was updated or {@link Mono#empty()}, if not found.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	default <T> Mono<T> findAndReplace(Query query, T replacement) {
@@ -732,6 +797,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @return the converted object that was updated or {@link Mono#empty()}, if not found. Depending on the value of
 	 *         {@link FindAndReplaceOptions#isReturnNew()} this will either be the object as it was before the update or
 	 *         as it is after the update.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	default <T> Mono<T> findAndReplace(Query query, T replacement, FindAndReplaceOptions options) {
@@ -802,6 +869,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @return the converted object that was updated or {@link Mono#empty()}, if not found. Depending on the value of
 	 *         {@link FindAndReplaceOptions#isReturnNew()} this will either be the object as it was before the update or
 	 *         as it is after the update.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given replacement value.
 	 * @since 2.1
 	 */
 	default <S, T> Mono<T> findAndReplace(Query query, S replacement, FindAndReplaceOptions options, Class<S> entityType,
@@ -838,8 +907,10 @@ 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}.
 	 *
@@ -855,7 +926,8 @@ 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}.
 	 *
@@ -873,96 +945,8 @@ 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 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} 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);
-
-	/**
-	 * 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 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} 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);
-
-	/**
-	 * 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.reactivestreams.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 #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 />
-	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
-	 * transactions.
-	 *
-	 * @param entityClass must not be {@literal null}.
-	 * @return a {@link Mono} emitting the estimated number of documents.
-	 * @since 3.1
-	 */
-	default Mono<Long> estimatedCount(Class<?> entityClass) {
-
-		Assert.notNull(entityClass, "Entity class must not be null!");
-		return estimatedCount(getCollectionName(entityClass));
-	}
-
-	/**
-	 * 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.
-	 *
-	 * @param collectionName must not be {@literal null}.
-	 * @return a {@link Mono} emitting the estimated number of documents.
-	 * @since 3.1
-	 */
-	Mono<Long> estimatedCount(String collectionName);
-
-	/**
-	 * Returns the number of documents for the given {@link Query} by querying the collection of the given entity class.
+	 * count all matches.
 	 * <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
@@ -973,11 +957,10 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *          {@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
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
-	default Mono<Long> exactCount(Query query, Class<?> entityClass) {
-		return exactCount(query, entityClass, getCollectionName(entityClass));
-	}
+	Mono<Long> count(Query query, Class<?> entityClass);
 
 	/**
 	 * Returns the number of documents for the given {@link Query} querying the given collection. The given {@link Query}
@@ -986,7 +969,8 @@ 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 />
+	 * 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
@@ -997,11 +981,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @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);
-	}
+	Mono<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
@@ -1009,7 +990,8 @@ 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 />
+	 * 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
@@ -1021,18 +1003,51 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @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);
+	Mono<Long> count(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 />
+	 * Estimate the number of documents, in the collection {@link #getCollectionName(Class) identified by the given type},
+	 * based on collection statistics.
+	 * <br />
+	 * Please make sure to read the MongoDB reference documentation about limitations on eg. sharded cluster or inside
+	 * transactions.
+	 *
+	 * @param entityClass must not be {@literal null}.
+	 * @return a {@link Mono} emitting the estimated number of documents.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
+	 * @since 3.1
+	 */
+	default Mono<Long> estimatedCount(Class<?> entityClass) {
+
+		Assert.notNull(entityClass, "Entity class must not be null!");
+		return estimatedCount(getCollectionName(entityClass));
+	}
+
+	/**
+	 * 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.
+	 *
+	 * @param collectionName must not be {@literal null}.
+	 * @return a {@link Mono} emitting the estimated number of documents.
+	 * @since 3.1
+	 */
+	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}.
+	 * <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.
@@ -1040,13 +1055,17 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param objectToSave the object to store in the collection. Must not be {@literal null}.
 	 * @return the inserted object.
 	 * @throws IllegalArgumentException in case the {@code objectToSave} is collection-like.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	<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.
@@ -1063,7 +1082,9 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *
 	 * @param batchToSave the batch of objects to save. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
-	 * @return the inserted objects .
+	 * @return the inserted objects.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	<T> Flux<T> insert(Collection<? extends T> batchToSave, Class<?> entityClass);
 
@@ -1082,17 +1103,22 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *
 	 * @param objectsToSave the list of objects to save. Must not be {@literal null}.
 	 * @return the saved objects.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} for the given objects.
 	 */
 	<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}.
@@ -1106,6 +1132,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param batchToSave the publisher which provides objects to save. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the inserted objects.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} for the type.
 	 */
 	<T> Flux<T> insertAll(Mono<? extends Collection<? extends T>> batchToSave, Class<?> entityClass);
 
@@ -1129,32 +1157,38 @@ 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}.
 	 * @return the saved object.
 	 * @throws IllegalArgumentException in case the {@code objectToSave} is collection-like.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	<T> Mono<T> save(T objectToSave);
 
 	/**
 	 * 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}.
@@ -1165,30 +1199,34 @@ 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.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	<T> Mono<T> save(Mono<? extends T> objectToSave);
 
 	/**
 	 * 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}.
@@ -1208,6 +1246,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *          the existing object. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use. Must not be {@literal null}.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 * @since 3.0
 	 * @see Update
 	 * @see AggregationUpdate
@@ -1262,6 +1302,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *          the existing. Must not be {@literal null}.
 	 * @param entityClass class that determines the collection to use.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 * @since 3.0
 	 * @see Update
 	 * @see AggregationUpdate
@@ -1317,6 +1359,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param entityClass class of the pojo to be operated on. Must not be {@literal null}.
 	 * @return the {@link UpdateResult} which lets you access the results of the previous write.
 	 * @since 3.0
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 * @see Update
 	 * @see AggregationUpdate
 	 */
@@ -1363,6 +1407,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *
 	 * @param object must not be {@literal null}.
 	 * @return the {@link DeleteResult} which lets you access the results of the previous delete.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	Mono<DeleteResult> remove(Object object);
 
@@ -1380,6 +1426,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *
 	 * @param objectToRemove must not be {@literal null}.
 	 * @return the {@link DeleteResult} which lets you access the results of the previous delete.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given object type.
 	 */
 	Mono<DeleteResult> remove(Mono<? extends Object> objectToRemove);
 
@@ -1399,6 +1447,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param query the query document that specifies the criteria used to remove a record.
 	 * @param entityClass class that determines the collection to use.
 	 * @return the {@link DeleteResult} which lets you access the results of the previous delete.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	Mono<DeleteResult> remove(Query query, Class<?> entityClass);
 
@@ -1442,6 +1492,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param query the query document that specifies the criteria used to find and remove documents.
 	 * @param entityClass class of the pojo to be operated on.
 	 * @return the {@link Flux} converted objects deleted by this operation.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	<T> Flux<T> findAllAndRemove(Query query, Class<T> entityClass);
 
@@ -1461,9 +1513,11 @@ 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}.
 	 *
@@ -1471,6 +1525,8 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *          specification.
 	 * @param entityClass the parametrized type of the returned {@link Flux}.
 	 * @return the {@link Flux} of converted objects.
+	 * @throws org.springframework.data.mapping.MappingException if the target collection name cannot be
+	 *           {@link #getCollectionName(Class) derived} from the given type.
 	 */
 	<T> Flux<T> tail(Query query, Class<T> entityClass);
 
@@ -1478,9 +1534,11 @@ 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}.
 	 *
@@ -1496,9 +1554,11 @@ 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.
 	 *
@@ -1518,9 +1578,11 @@ 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.
 	 *
@@ -1541,9 +1603,11 @@ 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.
 	 *
@@ -1573,9 +1637,7 @@ 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);
 
@@ -1593,9 +1655,7 @@ 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);
 
@@ -1611,6 +1671,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 *
 	 * @param entityClass must not be {@literal null}.
 	 * @return never {@literal null}.
+	 * @throws org.springframework.data.mapping.MappingException if the collection name cannot be derived from the type.
 	 * @since 2.1
 	 */
 	String getCollectionName(Class<?> entityClass);

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

@@ -41,6 +41,10 @@ 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) {
 
@@ -64,6 +68,10 @@ 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) {
 
@@ -72,6 +80,10 @@ 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) {
 
@@ -80,6 +92,10 @@ 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() {
 
@@ -88,6 +104,10 @@ 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

@@ -42,6 +42,10 @@ 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) {
 
@@ -79,6 +83,10 @@ 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) {
 
@@ -88,6 +96,10 @@ 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) {
 
@@ -97,16 +109,28 @@ 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() {
 
@@ -117,6 +141,10 @@ 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,
@@ -124,6 +152,10 @@ 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) {
 
@@ -133,11 +165,19 @@ 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) {
 
@@ -147,6 +187,10 @@ 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) {
 
@@ -156,6 +200,10 @@ 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) {
 
@@ -165,6 +213,10 @@ 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

@@ -75,16 +75,28 @@ 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

@@ -0,0 +1,74 @@
+/*
+ * 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

@@ -97,10 +97,18 @@ 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.");
@@ -125,20 +133,36 @@ 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);
@@ -162,36 +186,64 @@ 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.
@@ -44,6 +44,9 @@ 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

@@ -334,6 +334,9 @@ 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) {
@@ -414,6 +417,9 @@ 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) {
@@ -494,6 +500,9 @@ 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) {
@@ -574,6 +583,9 @@ 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) {
@@ -654,6 +666,9 @@ 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) {
@@ -734,6 +749,9 @@ 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) {

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

@@ -99,6 +99,10 @@ 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";

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

@@ -226,7 +226,8 @@ 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}.
 	 *
@@ -434,6 +435,18 @@ 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.
 	 *
@@ -712,7 +725,8 @@ 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.
 	 *
@@ -727,6 +741,10 @@ 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));
@@ -770,6 +788,10 @@ 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

@@ -0,0 +1,108 @@
+/*
+ * 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

@@ -80,16 +80,28 @@ 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

@@ -339,6 +339,9 @@ 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

@@ -77,6 +77,10 @@ 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

@@ -64,6 +64,9 @@ 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

@@ -242,26 +242,48 @@ 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/ArithmeticOperators.java

@@ -800,26 +800,6 @@ public class ArithmeticOperators {
 			return usesFieldRef() ? Cosh.coshOf(fieldReference, unit) : Cosh.coshOf(expression, unit);
 		}
 
-		/**
-		 * Creates new {@link AggregationExpression} that calculates the inverse cosine of a numeric value.
-		 *
-		 * @return new instance of {@link ACos}.
-		 * @since 3.4
-		 */
-		public ACos acos() {
-			return usesFieldRef() ? ACos.acosOf(fieldReference) : ACos.acosOf(expression);
-		}
-
-		/**
-		 * Creates new {@link AggregationExpression} that calculates the inverse hyperbolic cosine of a numeric value.
-		 *
-		 * @return new instance of {@link ACosh}.
-		 * @since 3.4
-		 */
-		public ACosh acosh() {
-			return usesFieldRef() ? ACosh.acoshOf(fieldReference) : ACosh.acoshOf(expression);
-		}
-
 		/**
 		 * Creates new {@link AggregationExpression} that calculates the tangent of a numeric value given in
 		 * {@link AngularUnit#RADIANS radians}.
@@ -2482,6 +2462,7 @@ public class ArithmeticOperators {
 		}
 	}
 
+
 	/**
 	 * An {@link AggregationExpression expression} that calculates the cosine of a value that is measured in radians.
 	 *
@@ -2684,108 +2665,6 @@ public class ArithmeticOperators {
 		}
 	}
 
-	/**
-	 * An {@link AggregationExpression expression} that calculates the inverse cosine of a value.
-	 *
-	 * @author Divya Srivastava
-	 * @since 3.4
-	 */
-	public static class ACos extends AbstractAggregationExpression {
-
-		private ACos(Object value) {
-			super(value);
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse cosine of a value.
-		 *
-		 * @param fieldReference the name of the {@link Field field} that resolves to a numeric value.
-		 * @return new instance of {@link ACos}.
-		 */
-		public static ACos acosOf(String fieldReference) {
-
-			Assert.notNull(fieldReference, "FieldReference must not be null!");
-			return new ACos(Fields.field(fieldReference));
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse cosine of a value.
-		 * <br />
-		 *
-		 * @param expression the {@link AggregationExpression expression} that resolves to a numeric value.
-		 * @return new instance of {@link ACos}.
-		 */
-		public static ACos acosOf(AggregationExpression expression) {
-			return new ACos(expression);
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse cosine of a value.
-		 *
-		 * @param value anything ({@link Field field}, {@link AggregationExpression expression}, ...) that resolves to a
-		 *          numeric value.
-		 * @return new instance of {@link ACos}.
-		 */
-		public static ACos acosOf(Number value) {
-			return new ACos(value);
-		}
-
-		@Override
-		protected String getMongoMethod() {
-			return "$acos";
-		}
-	}
-
-	/**
-	 * An {@link AggregationExpression expression} that calculates the inverse hyperbolic cosine of a value.
-	 *
-	 * @author Divya Srivastava
-	 * @since 3.4
-	 */
-	public static class ACosh extends AbstractAggregationExpression {
-
-		private ACosh(Object value) {
-			super(value);
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse hyperbolic cosine of a value.
-		 *
-		 * @param fieldReference the name of the {@link Field field} that resolves to a numeric value.
-		 * @return new instance of {@link ACosh}.
-		 */
-		public static ACosh acoshOf(String fieldReference) {
-			return new ACosh(Fields.field(fieldReference));
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse hyperbolic cosine of a value.
-		 * <br />
-		 *
-		 * @param expression the {@link AggregationExpression expression} that resolves to a numeric value.
-		 * @return new instance of {@link ACosh}.
-		 */
-		public static ACosh acoshOf(AggregationExpression expression) {
-			return new ACosh(expression);
-		}
-
-		/**
-		 * Creates a new {@link AggregationExpression} that calculates the inverse hyperbolic cosine of a value.
-		 *
-		 * @param value anything ({@link Field field}, {@link AggregationExpression expression}, ...) that resolves to a
-		 *          numeric value.
-		 * @return new instance of {@link ACosh}.
-		 */
-		public static ACosh acoshOf(Object value) {
-			return new ACosh(value);
-		}
-
-		@Override
-		protected String getMongoMethod() {
-			return "$acosh";
-		}
-	}
-
 	/**
 	 * An {@link AggregationExpression expression} that calculates the tangent of a value that is measured in radians.
 	 *
@@ -2975,6 +2854,7 @@ public class ArithmeticOperators {
 			return new ATan2((Collections.singletonList(expression)));
 		}
 
+
 		/**
 		 * Creates a new {@link AggregationExpression} that calculates the inverse tangent of of y / x, where y and x are
 		 * the first and second values passed to the expression respectively.

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

@@ -35,7 +35,6 @@ import org.springframework.util.Assert;
  * @author Christoph Strobl
  * @author Mark Paluch
  * @author Shashank Sharma
- * @author Divya Srivastava
  * @since 1.0
  */
 public class ArrayOperators {
@@ -363,38 +362,6 @@ 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
@@ -645,6 +612,10 @@ 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);
@@ -765,6 +736,10 @@ 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) {
 
@@ -773,6 +748,10 @@ 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) {
 
@@ -781,6 +760,10 @@ 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) {
 
@@ -789,6 +772,10 @@ 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) {
 
@@ -797,6 +784,10 @@ 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) {
 
@@ -805,6 +796,10 @@ 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) {
 
@@ -1249,6 +1244,9 @@ 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) {
 
@@ -1435,6 +1433,9 @@ 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));
@@ -1802,117 +1803,13 @@ public class ArrayOperators {
 			return new ArrayToObject(expression);
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AbstractAggregationExpression#getMongoMethod()
+		 */
 		@Override
 		protected String getMongoMethod() {
 			return "$arrayToObject";
 		}
 	}
-	
-	/**
-	 * {@link AggregationExpression} for {@code $first} that returns the first element in an array. <br />
-	 * <strong>NOTE:</strong> Requires MongoDB 4.4 or later.
-	 *
-	 * @author Divya Srivastava
-	 * @author Christoph Strobl
-	 * @since 3.4
-	 */
-	public static class First extends AbstractAggregationExpression {
-
-		private First(Object value) {
-			super(value);
-		}
-
-		/**
-		 * Returns the first element in the given array.
-		 *
-		 * @param array must not be {@literal null}.
-		 * @return new instance of {@link First}.
-		 */
-		public static First first(Object array) {
-			return new First(array);
-		}
-
-		/**
-		 * Returns the first element in the array pointed to by the given {@link Field field reference}.
-		 *
-		 * @param fieldReference must not be {@literal null}.
-		 * @return new instance of {@link First}.
-		 */
-		public static First firstOf(String fieldReference) {
-			return new First(Fields.field(fieldReference));
-		}
-
-		/**
-		 * Returns the first element of the array computed by the given {@link AggregationExpression expression}.
-		 *
-		 * @param expression must not be {@literal null}.
-		 * @return new instance of {@link First}.
-		 */
-		public static First firstOf(AggregationExpression expression) {
-			return new First(expression);
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.aggregation.AbstractAggregationExpression#getMongoMethod()
-		 */
-		@Override
-		protected String getMongoMethod() {
-			return "$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

@@ -88,6 +88,9 @@ 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) {
 
@@ -104,6 +107,10 @@ 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";
@@ -137,21 +144,33 @@ 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);
@@ -173,6 +192,9 @@ 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);
@@ -201,6 +223,9 @@ 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);
@@ -245,6 +270,9 @@ 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

@@ -84,6 +84,9 @@ 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) {
 
@@ -100,6 +103,10 @@ 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";
@@ -136,21 +143,33 @@ 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);
@@ -172,6 +191,9 @@ 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);
@@ -199,6 +221,9 @@ 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

@@ -141,6 +141,9 @@ 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) {
 
@@ -156,6 +159,9 @@ 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();
@@ -448,6 +454,9 @@ 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) {
 
@@ -531,6 +540,10 @@ 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) {
 
@@ -623,6 +636,9 @@ 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);
@@ -649,6 +665,9 @@ 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

@@ -275,6 +275,10 @@ 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) {
 
@@ -404,6 +408,9 @@ 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!");
@@ -411,6 +418,9 @@ public class ConditionalOperators {
 				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) {
 
@@ -429,16 +439,25 @@ public class ConditionalOperators {
 				return ifNull(expression);
 			}
 
+			/* (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ConditionalOperators.IfNull.ThenBuilder#then(java.lang.Object)
+			 */
 			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(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!");
@@ -524,6 +543,9 @@ 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) {
 
@@ -611,6 +633,10 @@ 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) {
 
@@ -649,10 +675,7 @@ public class ConditionalOperators {
 			if (value instanceof CriteriaDefinition) {
 
 				Document mappedObject = context.getMappedObject(((CriteriaDefinition) value).getCriteriaObject());
-				List<Object> clauses = new ArrayList<Object>();
-
-				clauses.addAll(getClauses(context, mappedObject));
-
+				List<Object> clauses = getClauses(context, mappedObject);
 				return clauses.size() == 1 ? clauses.get(0) : clauses;
 			}
 
@@ -679,7 +702,9 @@ public class ConditionalOperators {
 
 			if (predicate instanceof List) {
 
-				List<Object> args = new ArrayList<Object>();
+				List<?> predicates = (List<?>) predicate;
+				List<Object> args = new ArrayList<Object>(predicates.size());
+
 				for (Object clause : (List<?>) predicate) {
 					if (clause instanceof Document) {
 						args.addAll(getClauses(context, (Document) clause));
@@ -697,14 +722,14 @@ public class ConditionalOperators {
 						continue;
 					}
 
-					List<Object> args = new ArrayList<Object>();
+					List<Object> args = new ArrayList<Object>(2);
 					args.add("$" + key);
 					args.add(nested.get(s));
 					clauses.add(new Document(s, args));
 				}
 			} else if (!isKeyword(key)) {
 
-				List<Object> args = new ArrayList<Object>();
+				List<Object> args = new ArrayList<Object>(2);
 				args.add("$" + key);
 				args.add(predicate);
 				clauses.add(new Document("$eq", args));
@@ -889,6 +914,9 @@ 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) {
 
@@ -898,6 +926,9 @@ 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) {
 
@@ -906,6 +937,9 @@ 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) {
 
@@ -914,6 +948,9 @@ 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) {
 
@@ -922,6 +959,9 @@ 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) {
 
@@ -930,6 +970,9 @@ 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) {
 
@@ -938,6 +981,9 @@ 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) {
 
@@ -946,6 +992,9 @@ 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) {
 
@@ -953,6 +1002,9 @@ 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) {
 
@@ -960,6 +1012,9 @@ 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) {
 

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

@@ -43,6 +43,9 @@ public class CountOperation implements FieldsExposingAggregationOperation {
 		this.fieldName = fieldName;
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 		return new Document(getOperator(), fieldName);
@@ -53,6 +56,9 @@ public class CountOperation implements FieldsExposingAggregationOperation {
 		return "$count";
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#getFields()
+	 */
 	@Override
 	public ExposedFields getFields() {
 		return ExposedFields.from(new ExposedField(fieldName, true));

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

@@ -91,7 +91,8 @@ public class DateOperators {
 	}
 
 	/**
-	 * Take the given value as date. <br />
+	 * Take the given value as date.
+	 * <br />
 	 * This can be one of:
 	 * <ul>
 	 * <li>{@link java.util.Date}</li>
@@ -189,7 +190,7 @@ public class DateOperators {
 		 * representing an Olson Timezone Identifier or UTC Offset.
 		 *
 		 * @param value the plain timezone {@link String}, a {@link Field} holding the timezone or an
-		 *          {@link AggregationExpression} resulting in the timezone.
+		 * {@link AggregationExpression} resulting in the timezone.
 		 * @return new instance of {@link Timezone}.
 		 */
 		public static Timezone valueOf(Object value) {
@@ -332,7 +333,8 @@ public class DateOperators {
 		}
 
 		/**
-		 * Creates new {@link DateOperatorFactory} for given {@code value} that resolves to a Date. <br />
+		 * Creates new {@link DateOperatorFactory} for given {@code value} that resolves to a Date.
+		 * <br />
 		 * <ul>
 		 * <li>{@link java.util.Date}</li>
 		 * <li>{@link java.util.Calendar}</li>
@@ -2086,6 +2088,20 @@ public class DateOperators {
 			return second(expression);
 		}
 
+		/**
+		 * Set the {@literal millisecond} to the given value which must resolve to a value in range {@code 0 - 999}. Can be
+		 * a simple value, {@link Field field reference} or {@link AggregationExpression expression}.
+		 *
+		 * @param millisecond must not be {@literal null}.
+		 * @return new instance.
+		 * @throws IllegalArgumentException if given {@literal millisecond} is {@literal null}
+		 * @deprecated since 3.2, use {@link #millisecond(Object)} instead.
+		 */
+		@Deprecated
+		default T milliseconds(Object millisecond) {
+			return millisecond(millisecond);
+		}
+
 		/**
 		 * Set the {@literal millisecond} to the given value which must resolve to a value in range {@code 0 - 999}. Can be
 		 * a simple value, {@link Field field reference} or {@link AggregationExpression expression}.
@@ -2097,6 +2113,19 @@ public class DateOperators {
 		 */
 		T millisecond(Object millisecond);
 
+		/**
+		 * Set the {@literal millisecond} to the value resolved by following the given {@link Field field reference}.
+		 *
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance.
+		 * @throws IllegalArgumentException if given {@literal fieldReference} is {@literal null}.
+		 * @deprecated since 3.2,use {@link #millisecondOf(String)} instead.
+		 */
+		@Deprecated
+		default T millisecondsOf(String fieldReference) {
+			return millisecondOf(fieldReference);
+		}
+
 		/**
 		 * Set the {@literal millisecond} to the value resolved by following the given {@link Field field reference}.
 		 *
@@ -2106,7 +2135,20 @@ public class DateOperators {
 		 * @since 3.2
 		 */
 		default T millisecondOf(String fieldReference) {
-			return millisecond(Fields.field(fieldReference));
+			return milliseconds(Fields.field(fieldReference));
+		}
+
+		/**
+		 * Set the {@literal millisecond} to the result of the given {@link AggregationExpression expression}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance.
+		 * @throws IllegalArgumentException if given {@literal expression} is {@literal null}.
+		 * @deprecated since 3.2, use {@link #millisecondOf(AggregationExpression)} instead.
+		 */
+		@Deprecated
+		default T millisecondsOf(AggregationExpression expression) {
+			return millisecondOf(expression);
 		}
 
 		/**
@@ -2118,7 +2160,7 @@ public class DateOperators {
 		 * @since 3.2
 		 */
 		default T millisecondOf(AggregationExpression expression) {
-			return millisecond(expression);
+			return milliseconds(expression);
 		}
 	}
 
@@ -2129,7 +2171,7 @@ public class DateOperators {
 	 * @author Matt Morrissette
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/</a>
 	 * @since 2.1
 	 */
 	public static class DateFromParts extends TimezonedDateAggregationExpression implements DateParts<DateFromParts> {
@@ -2304,7 +2346,7 @@ public class DateOperators {
 	 * @author Matt Morrissette
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/</a>
 	 * @since 2.1
 	 */
 	public static class IsoDateFromParts extends TimezonedDateAggregationExpression
@@ -2480,7 +2522,7 @@ public class DateOperators {
 	 * @author Matt Morrissette
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/dateToParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateToParts/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/dateToParts/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateToParts/</a>
 	 * @since 2.1
 	 */
 	public static class DateToParts extends TimezonedDateAggregationExpression {
@@ -2561,7 +2603,7 @@ public class DateOperators {
 	 * @author Matt Morrissette
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromString/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromString/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromString/">https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromString/</a>
 	 * @since 2.1
 	 */
 	public static class DateFromString extends TimezonedDateAggregationExpression {

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

@@ -46,6 +46,10 @@ abstract class DocumentEnhancingOperation implements InheritsFieldsAggregationOp
 		}
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 
@@ -67,6 +71,10 @@ abstract class DocumentEnhancingOperation implements InheritsFieldsAggregationOp
 	 */
 	protected abstract String mongoOperator();
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
 	public String getOperator() {
 		return mongoOperator();
@@ -79,6 +87,10 @@ abstract class DocumentEnhancingOperation implements InheritsFieldsAggregationOp
 		return this.valueMap;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#getFields()
+	 */
 	@Override
 	public ExposedFields getFields() {
 		return exposedFields;