Volatile Keyword

Volatile is a modifier keyword. Volatile can be use with only variables not with class or method names. When a variable declared as volatile it means, the value of the variable should be taken from main memory of its stack not from cached thread-locally. A variable value will be modified by different threads. This keyword has to declare in synchronized block.

public class TryCatch {

       private static volatile int volatileVariable = 0;

       public static void main(String[] args) {

              new Listener().start();

              new Maker().start();

       }

       static class Listener extends Thread {

              @Override

              public void run() {

                     int LocalVariable = volatileVariable;

                     while (LocalVariable < 5) {

                           if (LocalVariable != volatileVariable) {

                                  System.out.println("Got Change for volatileVariable : " + volatileVariable);

                                  LocalVariable = volatileVariable;

                           }

                     }

              }

       }

       static class Maker extends Thread {

              @Override

              public void run() {

                    int localVariable = volatileVariable;

                     while (volatileVariable < 5) {

                           System.out.println("Incrementing volatileVariable to " + (localVariable + 1));

                           volatileVariable = ++localVariable;

                           try {

                                  Thread.sleep(1000);

                           } catch (InterruptedException e) {

                                  e.printStackTrace();

                           }

                     }

              }

       }

}