Initial commit

build.gradle

@@ -0,0 +1,21 @@
+plugins {
+    id 'java'
+}
+
+group = 'com.hithomelabs.dsa'
+version = '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation platform('org.junit:junit-bom:5.10.0')
+    compileOnly 'org.projectlombok:lombok:1.18.34'
+    annotationProcessor 'org.projectlombok:lombok:1.18.34'
+    testImplementation 'org.junit.jupiter:junit-jupiter'
+}
+
+test {
+    useJUnitPlatform()
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Sun Aug 03 17:08:53 IST 2025
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original 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.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$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=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'corejava'
+

src/main/java/com/hithomelabs/dsa/concurrency/DeadLock.java

@@ -0,0 +1,106 @@
+package com.hithomelabs.dsa.concurrency;
+/*
+    * * Example of deadlock
+ */
+
+import lombok.AllArgsConstructor;
+
+class Aloo{
+
+    public void alooSong(){
+        System.out.println("Aloo ... le lo");
+    }
+
+}
+
+class Kanda{
+
+    public void kandaSong(){
+        System.out.println("kandaa ... le looo");
+    }
+}
+
+@AllArgsConstructor
+class Vendor1 implements Runnable {
+
+    Aloo aloo;
+    Kanda kanda;
+
+    @Override
+    public void run() {
+        System.out.println("Vendor1 singing");
+        synchronized (aloo) {
+            aloo.alooSong();
+
+            // * *  sleep
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+
+            synchronized (kanda) {
+                kanda.kandaSong();
+            }
+        }
+    }
+}
+
+@AllArgsConstructor
+class Vendor2 implements Runnable{
+
+    Aloo aloo;
+    Kanda kanda;
+
+    @Override
+    public void run() {
+        System.out.println("Vendor2 singing");
+        synchronized (kanda){
+            kanda.kandaSong();
+
+            // * * sleep
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+
+            synchronized (aloo){
+                aloo.alooSong();
+            }
+
+        }
+    }
+}
+
+public class DeadLock {
+    public static void main(String[] args) throws InterruptedException {
+
+        // * * Shared resources
+        Aloo aaloo = new Aloo();
+        Kanda kanda = new Kanda();
+
+        // * * Declaring the two threads, with 2 vendors
+        Thread t1 = new Thread(new Vendor1(aaloo, kanda));
+        Thread t2 = new Thread(new Vendor2(aaloo, kanda));
+
+        t1.start();
+        t2.start();
+
+        // * * Looking at the state the threads are in
+        Thread.sleep(500);
+        System.out.println(t1 + ":" + t1.getState());
+        System.out.println(t2 + ":" + t2.getState());
+        System.out.println("Main thread state :" + Thread.currentThread().getState());
+
+        // * * Looking at the state the threads are in
+        Thread.sleep(1000);
+        System.out.println(t1 + ":" + t1.getState());
+        System.out.println(t2 + ":" + t2.getState());
+        System.out.println("Main thread state :" + Thread.currentThread().getState());
+
+        t1.join();
+        t2.join();
+
+    }
+}

src/main/java/com/hithomelabs/dsa/concurrency/DeadLockExampleWithLock.java

@@ -0,0 +1,112 @@
+package com.hithomelabs.dsa.concurrency;
+
+/*
+    * * An example where one vendor gets the lock but deadlock is avoided
+ */
+
+import lombok.AllArgsConstructor;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+class Paper{
+
+    private static Lock lock = new ReentrantLock();
+    private String message;
+
+    public String procurePaper() {
+        boolean hasLock = false;
+        try{
+            if(lock.tryLock(500, TimeUnit.MILLISECONDS)){
+                hasLock = true;
+                return "writing on paper ...";
+            }
+            else{
+                return "Could not get lock";
+            }
+        }catch (Exception e){
+            System.out.println(e.getMessage());
+        }
+        finally {
+            if (hasLock)
+                lock.unlock();
+        }
+        return "";
+    }
+
+}
+
+class Pen{
+
+    private String message;
+    private static Lock lock = new ReentrantLock();
+
+    public String procurePen(){
+        boolean hasLock = false;
+        try{
+            if(lock.tryLock(500,TimeUnit.MILLISECONDS)){
+                hasLock = true;
+                Thread.sleep(5000);
+                return "Writing with pen ...";
+            }
+            else{
+                return "Could not get lock";
+            }
+        }
+        catch(Exception e){
+            System.out.println(e.getMessage());
+        }
+        finally {
+            if(hasLock)
+                lock.unlock();
+        }
+        return "";
+    }
+
+}
+
+@AllArgsConstructor
+class VendorWithLock1 implements Runnable{
+
+    Pen pen;
+    Paper paper;
+
+    @Override
+    public void run() {
+        System.out.println(Thread.currentThread() + paper.procurePaper());
+        System.out.println(Thread.currentThread() + pen.procurePen());
+    }
+}
+
+@AllArgsConstructor
+class VendorWithLock2 implements Runnable{
+
+    Pen pen;
+    Paper paper;
+
+    @Override
+    public void run() {
+        System.out.println(Thread.currentThread() + pen.procurePen());
+        System.out.println(Thread.currentThread() + paper.procurePaper());
+    }
+}
+
+public class DeadLockExampleWithLock {
+
+    public static void main(String[] args) throws InterruptedException {
+        // * * Shared resources
+        Pen pen = new Pen();
+        Paper paper = new Paper();
+
+        // * * Declaring the two threads, with 2 vendors
+        Thread t1 = new Thread(new VendorWithLock1(pen, paper));
+        Thread t2 = new Thread(new VendorWithLock2(pen, paper));
+
+        t1.start();
+        t2.start();
+
+        t1.join();
+        t2.join();
+    }
+}

src/main/java/com/hithomelabs/dsa/concurrency/Drop.java

@@ -0,0 +1,93 @@
+package com.hithomelabs.dsa.concurrency;
+
+class Producer implements Runnable{
+
+    Drop drop;
+
+    Producer(Drop drop){
+        this.drop = drop;
+    }
+
+    // This is the produce method
+
+    @Override
+    public  void run() {
+
+        for (int i = 0; i < 1000; i++) {
+            try {
+                drop.setMessage("Produced");
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+    }
+}
+
+
+class Consumer implements Runnable{
+
+    Drop drop;
+
+    Consumer(Drop drop){
+        this.drop = drop;
+    }
+
+    @Override
+    public void run() {
+        for (int i = 0; i < 1000; i++) {
+            try {
+                drop.consumeMessage();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}
+
+public class Drop {
+
+    private String message;
+    private boolean consumed = true;
+
+    public synchronized void setMessage(String message) throws InterruptedException {
+
+        // * *  Before producer produces message it has to check, if flag is true
+        // * * If flag is true, it means, good to produce
+        while(!consumed){
+            this.wait();
+        }
+        System.out.println(message);
+        this.message = message;
+        // * * Notify once production is complete
+        consumed = false;
+        this.notifyAll();
+    }
+
+    public synchronized void consumeMessage() throws InterruptedException{
+
+        // * * Will wait to consume unless
+        while(consumed){
+            this.wait();
+        }
+        System.out.println("Consumed message");
+        this.message = "";
+        consumed = true;
+        this.notifyAll();
+    }
+
+    public static void main(String[] args){
+
+        // * *  Shared object where producer drops produce and consumer consumes it
+        Drop drop = new Drop();
+
+        // * * providing the same drop object to both producer and consumer
+        Thread t1 = new Thread(new Producer(drop));
+        Thread t2 = new Thread(new Consumer(drop));
+
+        t2.start();
+        t1.start();
+
+    }
+
+}

src/main/java/com/hithomelabs/dsa/concurrency/InterruptExample.java

@@ -0,0 +1,32 @@
+package com.hithomelabs.dsa.concurrency;
+
+public class InterruptExample {
+
+    public static void main(String[] args) {
+        Thread gaanvKaWatchman  = new Thread(()->{
+            while(true){
+                try{
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    System.out.println("All is not well");
+                    System.out.println(e);
+                    return;
+                }
+                System.out.println("Aal izz well");
+            }
+        });
+        gaanvKaWatchman.start();
+        int counter = 5;
+        while(counter > 0){
+            try {
+                Thread.sleep(3000);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+            System.out.println("Looks like watchman is awake !! :: Checking in " + counter);
+            counter--;
+        }
+        System.out.println("Let me check ! Watchman is asleep, wake him up");
+        gaanvKaWatchman.interrupt();
+    }
+}

src/main/java/com/hithomelabs/dsa/concurrency/RaceCondition.java

@@ -0,0 +1,52 @@
+package com.hithomelabs.dsa.concurrency;
+
+/*
+    * * Using Threads often leads to unpredictable outputs (non-deterministic)
+    * * This is when two threads simultaneously execute a block of code
+    * * This is called a race condition and the block of code is called the critical section
+ */
+
+
+import lombok.Getter;
+
+public class RaceCondition {
+
+    // * * Creating a Runnable class Counter, having a field count that is incremented by the incrementCount method
+    // * * The run method increments count 1000 times
+
+    @Getter
+    static class Counter implements Runnable{
+
+        private int counter = 0;
+
+        // * * critical section
+        synchronized void incrementCounter(){
+            this.counter++;
+        }
+
+        @Override
+        public void run() {
+            for(int   i = 0; i < 1000; i++)
+                incrementCounter();
+        }
+    }
+
+    public static void main(String[] args) throws InterruptedException {
+
+        Counter counter = new Counter();
+
+        Thread t1 = new Thread(counter);
+        Thread t2 = new Thread(counter);
+
+        // * * both threads attempt to increments and save simultaneously
+        t1.start();
+        t2.start();
+
+        t1.join();
+        t2.join();
+
+        System.out.println(counter.getCounter());
+
+    }
+
+}

src/main/java/com/hithomelabs/dsa/concurrency/StaticMethods.java

@@ -0,0 +1,56 @@
+package com.hithomelabs.dsa.concurrency;
+import java.util.Arrays;
+
+public class StaticMethods {
+
+    public static void main(String[] args) throws InterruptedException {
+
+        // * *  we are going to look at important static methods of Threads
+
+        // * * sleep - Important thread life cycle method - passes control to other threads who want to execute
+        System.out.println("Sleeping for 1 second");
+        Thread.sleep(1000);
+
+        // * * Group 1 - Thread detail methods
+        System.out.println("Details of current thread: " + Thread.currentThread());
+
+        // * * Creating a runnable that sleeps fpr 5 and will use it to spawn some threads
+        Runnable sleepFor5 = () -> {
+            try {
+                System.out.println("Spawned new thread");
+                Thread.sleep(5000);
+                System.out.println("Slept for 5 seconds");
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        };
+
+        // * * Spawning some new threads
+        new Thread(sleepFor5).start();
+        new Thread(sleepFor5).start();
+        new Thread(sleepFor5).start();
+
+        Thread[] array = new Thread[4];
+
+        // * * Enumerating threads
+        Thread.enumerate(array);
+
+        System.out.println("Enumerating all known threads");
+        Arrays.stream(array).forEach(t -> {
+            System.out.println(t);
+            System.out.println(t.getState());
+        });
+
+        System.out.println("Thread active count: " + Thread.activeCount());
+        System.out.println("Will wait for other threads to join me");
+
+        Arrays.stream(array).filter(thread -> !thread.equals(Thread.currentThread())).forEach(thread -> {
+            try {
+                thread.join(); // * * Not a static method but a thread life cycle method
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        System.out.println("All threads are finished");
+    }
+}

src/main/java/com/hithomelabs/dsa/concurrency/ThreadSample.java

@@ -0,0 +1,38 @@
+package com.hithomelabs.dsa.concurrency;
+
+public class ThreadSample extends Thread {
+
+    @Override public void run(){
+        System.out.println("Hello this is called from: " + this.getClass());
+        System.out.println(Thread.currentThread());
+    }
+
+    public static void main(String[] args) {
+
+        /*
+        * * There are two ways to implement a thread, one is to extend the Thread class
+        * * Another one is to implement the Runnable Interface
+        */
+
+        ThreadSample thread = new ThreadSample();
+
+        // * * Thread.run() doesn't start a new thread; just calls the method
+        thread.run();
+
+        // * * Thread.start() starts a new thread
+        thread.start();
+
+        // * * Now attempting with Runnable:
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+                System.out.println("Hello this is called from: " + this.getClass());
+                System.out.println(Thread.currentThread());
+            }
+        }).start();
+
+        // * *  Can also be done using lamda expressions
+        new Thread(() -> System.out.println("Running from a lamda expression")).start();
+
+    }
+}

src/main/java/com/hithomelabs/dsa/concurrency/Volatile.java

@@ -0,0 +1,52 @@
+package com.hithomelabs.dsa.concurrency;
+
+import lombok.AllArgsConstructor;
+import lombok.Setter;
+
+@Setter
+class Flag{
+     boolean print = true;
+}
+
+@AllArgsConstructor
+class PrintLoop implements Runnable{
+
+    Flag flag;
+
+    @Override
+    public void run() {
+        int counter = 0;
+        while(flag.print){
+            System.out.println(++counter);
+        }
+    }
+}
+
+@AllArgsConstructor
+class FlagFalse implements Runnable{
+
+    Flag flag;
+
+    @Override
+    public void run() {
+        try {
+            Thread.sleep(1000);
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+        flag.setPrint(false);
+    }
+}
+
+public class Volatile {
+
+
+    public static void main(String[] args) {
+
+        Flag flag = new Flag();
+
+        new Thread(new PrintLoop(flag)).start();
+        new Thread(new FlagFalse(flag)).start();
+
+    }
+}