added code

core-java/streams/data-streams/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,18 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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
+# 
+#   http://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.
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar

core-java/streams/data-streams/README.md

@@ -0,0 +1,5 @@
+# Comprehensive Guide to Java Streams Code Examples
+ 
+## Related Blog Articles
+
+* [Comprehensive Guide to Java Streams](https://reflectoring.io/comprehensive-guide-to-java-streams/)

core-java/streams/data-streams/mvnw

@@ -0,0 +1,316 @@
+#!/bin/sh
+# ----------------------------------------------------------------------------
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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
+#
+#    http://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.
+# ----------------------------------------------------------------------------
+
+# ----------------------------------------------------------------------------
+# Maven Start Up Batch script
+#
+# Required ENV vars:
+# ------------------
+#   JAVA_HOME - location of a JDK home dir
+#
+# Optional ENV vars
+# -----------------
+#   M2_HOME - location of maven2's installed home dir
+#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
+#     e.g. to debug Maven itself, use
+#       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+#   MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+# ----------------------------------------------------------------------------
+
+if [ -z "$MAVEN_SKIP_RC" ] ; then
+
+  if [ -f /usr/local/etc/mavenrc ] ; then
+    . /usr/local/etc/mavenrc
+  fi
+
+  if [ -f /etc/mavenrc ] ; then
+    . /etc/mavenrc
+  fi
+
+  if [ -f "$HOME/.mavenrc" ] ; then
+    . "$HOME/.mavenrc"
+  fi
+
+fi
+
+# OS specific support.  $var _must_ be set to either true or false.
+cygwin=false;
+darwin=false;
+mingw=false
+case "`uname`" in
+  CYGWIN*) cygwin=true ;;
+  MINGW*) mingw=true;;
+  Darwin*) darwin=true
+    # Use /usr/libexec/java_home if available, otherwise fall back to /Library/Java/Home
+    # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
+    if [ -z "$JAVA_HOME" ]; then
+      if [ -x "/usr/libexec/java_home" ]; then
+        export JAVA_HOME="`/usr/libexec/java_home`"
+      else
+        export JAVA_HOME="/Library/Java/Home"
+      fi
+    fi
+    ;;
+esac
+
+if [ -z "$JAVA_HOME" ] ; then
+  if [ -r /etc/gentoo-release ] ; then
+    JAVA_HOME=`java-config --jre-home`
+  fi
+fi
+
+if [ -z "$M2_HOME" ] ; then
+  ## resolve links - $0 may be a link to maven's home
+  PRG="$0"
+
+  # need this for relative symlinks
+  while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+      PRG="$link"
+    else
+      PRG="`dirname "$PRG"`/$link"
+    fi
+  done
+
+  saveddir=`pwd`
+
+  M2_HOME=`dirname "$PRG"`/..
+
+  # make it fully qualified
+  M2_HOME=`cd "$M2_HOME" && pwd`
+
+  cd "$saveddir"
+  # echo Using m2 at $M2_HOME
+fi
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched
+if $cygwin ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --unix "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+fi
+
+# For Mingw, ensure paths are in UNIX format before anything is touched
+if $mingw ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME="`(cd "$M2_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+fi
+
+if [ -z "$JAVA_HOME" ]; then
+  javaExecutable="`which javac`"
+  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+    # readlink(1) is not available as standard on Solaris 10.
+    readLink=`which readlink`
+    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+      if $darwin ; then
+        javaHome="`dirname \"$javaExecutable\"`"
+        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+      else
+        javaExecutable="`readlink -f \"$javaExecutable\"`"
+      fi
+      javaHome="`dirname \"$javaExecutable\"`"
+      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      JAVA_HOME="$javaHome"
+      export JAVA_HOME
+    fi
+  fi
+fi
+
+if [ -z "$JAVACMD" ] ; then
+  if [ -n "$JAVA_HOME"  ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+      # IBM's JDK on AIX uses strange locations for the executables
+      JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+      JAVACMD="$JAVA_HOME/bin/java"
+    fi
+  else
+    JAVACMD="`\\unset -f command; \\command -v java`"
+  fi
+fi
+
+if [ ! -x "$JAVACMD" ] ; then
+  echo "Error: JAVA_HOME is not defined correctly." >&2
+  echo "  We cannot execute $JAVACMD" >&2
+  exit 1
+fi
+
+if [ -z "$JAVA_HOME" ] ; then
+  echo "Warning: JAVA_HOME environment variable is not set."
+fi
+
+CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
+
+# traverses directory structure from process work directory to filesystem root
+# first directory with .mvn subdirectory is considered project base directory
+find_maven_basedir() {
+
+  if [ -z "$1" ]
+  then
+    echo "Path not specified to find_maven_basedir"
+    return 1
+  fi
+
+  basedir="$1"
+  wdir="$1"
+  while [ "$wdir" != '/' ] ; do
+    if [ -d "$wdir"/.mvn ] ; then
+      basedir=$wdir
+      break
+    fi
+    # workaround for JBEAP-8937 (on Solaris 10/Sparc)
+    if [ -d "${wdir}" ]; then
+      wdir=`cd "$wdir/.."; pwd`
+    fi
+    # end of workaround
+  done
+  echo "${basedir}"
+}
+
+# concatenates all lines of a file
+concat_lines() {
+  if [ -f "$1" ]; then
+    echo "$(tr -s '\n' ' ' < "$1")"
+  fi
+}
+
+BASE_DIR=`find_maven_basedir "$(pwd)"`
+if [ -z "$BASE_DIR" ]; then
+  exit 1;
+fi
+
+##########################################################################################
+# Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+# This allows using the maven wrapper in projects that prohibit checking in binary data.
+##########################################################################################
+if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Found .mvn/wrapper/maven-wrapper.jar"
+    fi
+else
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
+    fi
+    if [ -n "$MVNW_REPOURL" ]; then
+      jarUrl="$MVNW_REPOURL/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+    else
+      jarUrl="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+    fi
+    while IFS="=" read key value; do
+      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+      esac
+    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Downloading from: $jarUrl"
+    fi
+    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+    if $cygwin; then
+      wrapperJarPath=`cygpath --path --windows "$wrapperJarPath"`
+    fi
+
+    if command -v wget > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found wget ... using wget"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            wget "$jarUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
+        else
+            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
+        fi
+    elif command -v curl > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found curl ... using curl"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            curl -o "$wrapperJarPath" "$jarUrl" -f
+        else
+            curl --user $MVNW_USERNAME:$MVNW_PASSWORD -o "$wrapperJarPath" "$jarUrl" -f
+        fi
+
+    else
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Falling back to using Java to download"
+        fi
+        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        # For Cygwin, switch paths to Windows format before running javac
+        if $cygwin; then
+          javaClass=`cygpath --path --windows "$javaClass"`
+        fi
+        if [ -e "$javaClass" ]; then
+            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Compiling MavenWrapperDownloader.java ..."
+                fi
+                # Compiling the Java class
+                ("$JAVA_HOME/bin/javac" "$javaClass")
+            fi
+            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                # Running the downloader
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Running MavenWrapperDownloader.java ..."
+                fi
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            fi
+        fi
+    fi
+fi
+##########################################################################################
+# End of extension
+##########################################################################################
+
+export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
+if [ "$MVNW_VERBOSE" = true ]; then
+  echo $MAVEN_PROJECTBASEDIR
+fi
+MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --path --windows "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+  [ -n "$MAVEN_PROJECTBASEDIR" ] &&
+    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+fi
+
+# Provide a "standardized" way to retrieve the CLI args that will
+# work with both Windows and non-Windows executions.
+MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $@"
+export MAVEN_CMD_LINE_ARGS
+
+WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+exec "$JAVACMD" \
+  $MAVEN_OPTS \
+  $MAVEN_DEBUG_OPTS \
+  -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
+  "-Dmaven.home=${M2_HOME}" \
+  "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"

core-java/streams/data-streams/mvnw.cmd

@@ -0,0 +1,188 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    http://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%USERPROFILE%\mavenrc_pre.bat" call "%USERPROFILE%\mavenrc_pre.bat" %*
+if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd" %*
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+
+FOR /F "usebackq tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% ^
+  %JVM_CONFIG_MAVEN_PROPS% ^
+  %MAVEN_OPTS% ^
+  %MAVEN_DEBUG_OPTS% ^
+  -classpath %WRAPPER_JAR% ^
+  "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" ^
+  %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%"=="" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%USERPROFILE%\mavenrc_post.bat" call "%USERPROFILE%\mavenrc_post.bat"
+if exist "%USERPROFILE%\mavenrc_post.cmd" call "%USERPROFILE%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%"=="on" pause
+
+if "%MAVEN_TERMINATE_CMD%"=="on" exit %ERROR_CODE%
+
+cmd /C exit /B %ERROR_CODE%

core-java/streams/data-streams/pom.xml

@@ -0,0 +1,11 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>io.pratik</groupId>
+  <artifactId>StreamingApp</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+  <name>StreamingApp</name>
+  <properties>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+</project>

core-java/streams/data-streams/src/main/java/io/pratik/ParallelStreamingApp.java

@@ -0,0 +1,21 @@
+package io.pratik;
+
+import java.util.List;
+
+public class ParallelStreamingApp {
+
+    public static void main(String[] args){
+        ParallelStreamingApp parallelStreamingApp = new ParallelStreamingApp();
+        parallelStreamingApp.processParallelStream();
+    }
+
+    public void processParallelStream(){
+        List<String> list = List.of("washing machine", "Television", "Laptop", "grocery");
+        list.parallelStream().forEach(System.out::println);
+        
+        list.parallelStream().forEachOrdered(System.out::println);
+
+
+    }
+    
+}

core-java/streams/data-streams/src/main/java/io/pratik/ReduceStreamingApp.java

@@ -0,0 +1,55 @@
+package io.pratik;
+
+import java.util.Arrays;
+import java.util.Optional;
+import java.util.OptionalDouble;
+import java.util.OptionalInt;
+import java.util.logging.Logger;
+
+public class ReduceStreamingApp {
+    private final Logger logger = Logger.getLogger(ReduceStreamingApp.class.getName());
+
+    public static void main(String[] args){
+        ReduceStreamingApp reduceStreamingApp = new ReduceStreamingApp();
+        reduceStreamingApp.sumElements();
+        reduceStreamingApp.joinString(",");
+        reduceStreamingApp.aggregateElements();
+    }
+
+    public void sumElements(){
+        int[] numbers = {5, 2, 8, 4,55, 9};
+        int sum = Arrays.stream(numbers).reduce(0, (a, b) -> a + b);
+        int sumWithMethodRef = Arrays.stream(numbers).reduce(0, Integer::sum); 
+
+        logger.info(sum + " " + sumWithMethodRef);
+    }
+
+    public void joinString(final String separator){
+        String[] strings = {"a", "b", "c", "d", "e"};
+
+        String joined = Arrays.stream(strings).reduce("", (a, b) -> {
+            return !"".equals(a)?  a + separator + b : b;
+           });
+
+        // a|b|c|d|e , better uses the Java 8 String.join :)
+        //String joined = String.join(separator, strings);
+
+        logger.info(joined);
+    }
+
+    public void aggregateElements(){
+        int[] numbers = {5, 2, 8, 4,55, 9};
+        int sum = Arrays.stream(numbers).sum();
+        OptionalInt max = Arrays.stream(numbers).max();
+        OptionalInt min = Arrays.stream(numbers).max();
+        long count = Arrays.stream(numbers).count();
+
+        OptionalDouble average  = Arrays.stream(numbers).average();
+
+        logger.info("sum:" + sum);
+        logger.info("max:" + max.getAsInt());
+        logger.info("min:" + min.getAsInt());
+        logger.info("count:" + count);
+        logger.info("average:" + average.getAsDouble());
+    }
+}

core-java/streams/data-streams/src/main/java/io/pratik/StreamMatcherApp.java

@@ -0,0 +1,39 @@
+package io.pratik;
+
+import java.util.logging.Logger;
+import java.util.stream.Stream;
+
+public class StreamMatcherApp {
+    private final Logger logger = Logger.getLogger(StreamMatcherApp.class.getName());
+    public static void main(String[] args) {
+        StreamMatcherApp streamMatcherApp = new StreamMatcherApp();
+        streamMatcherApp.findAnyMatch();
+        streamMatcherApp.findAllMatch();
+        streamMatcherApp.findNoneMatch();
+    }
+
+    public void findAnyMatch(){
+        Stream<String> productCategories = Stream.of("washing machine", "Television", "Laptop", "grocery", "essentials");
+	    
+        boolean isPresent = productCategories.anyMatch(e->e.equals("Laptop"));
+        logger.info("isPresent::"+isPresent);
+
+    }
+
+    public void findAllMatch(){
+        Stream<Integer> productCategories = Stream.of(4,5,7,9,10);
+	    
+        boolean allElementsMatch = productCategories.allMatch(e->e < 11);
+        logger.info("allElementsMatch::"+allElementsMatch);
+
+    }
+
+    public void findNoneMatch(){
+        Stream<Integer> productCategories = Stream.of(4,5,7,9,10);
+	    
+        boolean noElementsMatch = productCategories.noneMatch(e->e < 4);
+        logger.info("noElementsMatch::"+noElementsMatch);
+
+    }
+    
+}

core-java/streams/data-streams/src/main/java/io/pratik/StreamOrderingApp.java

@@ -0,0 +1,24 @@
+package io.pratik;
+
+import java.util.stream.Stream;
+
+public class StreamOrderingApp {
+    public static void main(String[] args) {
+        StreamOrderingApp streamOrderingApp = new StreamOrderingApp();
+
+        streamOrderingApp.sortElements();
+        streamOrderingApp.sortElementsWithComparator();
+    }
+
+    public void sortElements() {
+        Stream<Integer> productCategories = Stream.of(4,15,8,7,9,10);
+        Stream<Integer>  sortedStream = productCategories.sorted();
+        sortedStream.forEach(System.out::println);
+    }
+
+    public void sortElementsWithComparator() {
+        Stream<Integer> productCategories = Stream.of(4,15,8,7,9,10);
+        Stream<Integer>  sortedStream = productCategories.sorted((o1, o2) -> o2 - o1);
+        sortedStream.forEach(System.out::println);
+    }
+}

core-java/streams/data-streams/src/main/java/io/pratik/StreamingApp.java

@@ -0,0 +1,174 @@
+package io.pratik;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Optional;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+
+
+public class StreamingApp {
+
+	private final Logger logger = Logger.getLogger(StreamingApp.class.getName());
+
+	public static void main(String[] args) {
+		StreamingApp streamingApp = new StreamingApp();
+		/*streamingApp.createStreamFromArray();
+		streamingApp.createStreamFromCollection();
+		streamingApp.processStream();
+		streamingApp.collectFromStream();
+		streamingApp.mapStream();*/
+		streamingApp.flatmapStream();
+		//streamingApp.findFromStream();
+		//streamingApp.createFromNullable();
+		streamingApp.readFromFile("/Users/pratikdas/eclipse-workspace/StreamingApp/src/main/resources/sample.txt");
+	}
+	
+	public void streamTypes() {
+		
+		Stream<Integer> stream = Stream.of(3, 4, 6, 2);
+		
+		IntStream integerStream = IntStream.of(3, 4, 6, 2);
+		
+		LongStream longStream = LongStream.of(3l, 4l, 6l, 2l);
+
+		DoubleStream doubleStream = DoubleStream.of(3.0, 4.5, 6.7, 2.3);		
+	}
+	
+	public void createStreamFromArray() {
+		double[] elements = {3.0, 4.5, 6.7, 2.3};
+		
+		DoubleStream stream = Arrays.stream(elements);
+		
+		stream.forEach(e->System.out.println(e));
+	}
+	
+	public void createStreamFromCollection() {
+		Double[] elements = {3.0, 4.5, 6.7, 2.3};
+		
+		List<Double> elementsInCollection = Arrays.asList(elements);
+		
+		Stream<Double> stream = elementsInCollection.stream();
+		
+		Stream<Double> parallelStream = elementsInCollection.parallelStream();
+		
+		stream.forEach(e->System.out.println(e));
+		
+		parallelStream.forEach(e->System.out.println(e));
+	}
+	
+	public void createStreams() {
+		Stream<Integer> stream = Stream.of(3, 4, 6, 2);
+		
+		IntStream integerStream = IntStream.of(3, 4, 6, 2);
+		
+		LongStream longStream = LongStream.of(3l, 4l, 6l, 2l);
+
+		DoubleStream doubleStream = DoubleStream.of(3.0, 4.5, 6.7, 2.3);		
+	}
+
+	public void readFromFile(final String filePath) {
+		try (Stream<String> lines = Files.lines(Paths.get(filePath));){
+			lines.forEach(logger::info);
+		} catch (IOException e) {
+			logger.info("i/o error " + e);
+		}
+	}
+	
+	public void processStream() {
+		Double[] elements = {3.0, 4.5, 6.7, 2.3};
+		
+		Stream<Double> stream = Stream.of(elements);
+		
+		stream
+		.map(e->e.intValue())
+		.filter(e->e >3 )
+		.forEach(e->System.out.println(e));
+		          
+	}
+	
+	public void processStreamWithFlatMap() {
+		Double[] elements = {3.0, 4.5, 6.7, 2.3};
+		
+		Stream<Double> stream = Stream.of(elements);
+		
+	    
+		          
+	}
+
+	public void collectFromStream() {
+	
+		List<String> productCategories = Stream.of("washing machine", "Television", "Laptop", "grocery", "essentials")
+		                                    .collect(Collectors.toList());
+
+		productCategories.forEach(logger::info);							
+		
+	
+		          
+	}
+
+	public void printStream() {
+		Stream<String> productCategories = Stream.of("washing machine", "Television", "Laptop", "grocery", "essentials");
+	
+		productCategories.forEach(logger::info);   
+	}
+
+	public void mapStream() {
+		Stream<String> productCategories = Stream.of("washing machine", "Television", "Laptop", "grocery", "essentials");
+	
+		List<String> categoryCodes = productCategories.map(element->{
+			 String code = null;
+			 switch (element) {
+				case "washing machine" : code = "1";break;
+				case "Television" : code = "2";break;
+				case "Laptop" : code = "3";break;
+				case "grocery" : code = "4";break;
+				case "essentials" : code = "5";break;
+				case "default" : code = "6";
+			} 
+			return code;}).collect(Collectors.toList());
+
+			categoryCodes.forEach(logger::info);	
+    }
+
+	public void flatmapStream() {
+		List<List<String>> productByCategories = Arrays.asList( 
+			Arrays.asList("washing machine", "Television"), 
+			Arrays.asList("Laptop", "Camera", "Watch"), 
+			Arrays.asList("grocery", "essentials"));
+
+		List<String> products = productByCategories.stream().flatMap(Collection::stream
+		).collect(Collectors.toList());
+        
+		logger.info("flattened elements::"+products);
+		
+    }
+
+
+	public void findFromStream() {
+		Stream<String> productCategories = Stream.of("washing machine", "Television", "Laptop", "grocery", "essentials");
+
+		Optional<String> category = productCategories.findFirst();
+
+		if(category.isPresent()) logger.info(category.get());
+    }
+
+	public void createFromNullable() {
+		Stream<String> productCategories = Stream.ofNullable(null);
+
+		long count = productCategories.count();
+
+		logger.info("size=="+count);
+    }
+
+	
+
+}

core-java/streams/data-streams/src/main/java/io/pratik/UnboundedStreamingApp.java

@@ -0,0 +1,33 @@
+package io.pratik;
+
+import java.util.List;
+import java.util.UUID;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class UnboundedStreamingApp {
+    private final Logger logger = Logger.getLogger(UnboundedStreamingApp.class.getName());
+
+    public static void main(String[] args) {
+		UnboundedStreamingApp unboundedStreamingApp = new UnboundedStreamingApp();
+        unboundedStreamingApp.generateStreamingData();
+        unboundedStreamingApp.iterateStreamingData();
+    } 
+
+    public void generateStreamingData(){
+        Stream.generate(()->UUID.randomUUID().toString())
+        .limit(10)
+        .forEach(logger::info);
+    }
+
+    public void iterateStreamingData(){
+        Stream<Double> evenNumStream = Stream.iterate(2.0, element -> Math.pow(element, 2.0));
+
+        List<Double> collect = evenNumStream
+        .limit(5)
+        .collect(Collectors.toList());
+
+        collect.forEach(element->logger.info("value=="+element));
+    }
+}

core-java/streams/data-streams/src/main/resources/sample.txt

@@ -0,0 +1,10 @@
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file
+My sample file