diff --git a/core-java/src/main/java/com/baeldung/concurrent/volatilekeyword/SharedObject.java b/core-java/src/main/java/com/baeldung/concurrent/volatilekeyword/SharedObject.java new file mode 100644 index 0000000000..3f24df5059 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/concurrent/volatilekeyword/SharedObject.java @@ -0,0 +1,13 @@ +package com.baeldung.concurrent.volatilekeyword; + + +public class SharedObject { + private volatile int count=0; + + public void increamentCount(){ + count++; + } + public int getCount(){ + return count; + } +} diff --git a/core-java/src/test/java/com/baeldung/concurrent/volatilekeyword/SharedObjectManualTest.java b/core-java/src/test/java/com/baeldung/concurrent/volatilekeyword/SharedObjectManualTest.java new file mode 100644 index 0000000000..260a7c060b --- /dev/null +++ b/core-java/src/test/java/com/baeldung/concurrent/volatilekeyword/SharedObjectManualTest.java @@ -0,0 +1,99 @@ +package com.baeldung.concurrent.volatilekeyword; + +import org.junit.After; +import org.junit.Before; +import org.junit.Test; + +import static junit.framework.Assert.assertEquals; + +public class SharedObjectManualTest { + + SharedObject sharedObject; + int valueReadByThread2; + int valueReadByThread3; + + @Before + public void setUp(){ + sharedObject = new SharedObject(); + } + + @Test + public void whenOneThreadWrites_thenVolatileReadsFromMainMemory() throws InterruptedException { + Thread writer = new Thread(){ + public void run(){ + sharedObject.increamentCount(); + } + }; + writer.start(); + + + Thread readerOne = new Thread(){ + public void run(){ + try { + Thread.sleep(1000); + } catch (InterruptedException e) { + e.printStackTrace(); + } + valueReadByThread2= sharedObject.getCount(); + } + }; + readerOne.start(); + + Thread readerTwo = new Thread(){ + public void run(){ + try { + Thread.sleep(1000); + } catch (InterruptedException e) { + e.printStackTrace(); + } + valueReadByThread3=sharedObject.getCount(); + } + }; + readerTwo.start(); + + assertEquals(1,valueReadByThread2); + assertEquals(1,valueReadByThread3); + + } + + @Test + public void whenTwoThreadWrites_thenVolatileReadsFromMainMemory() throws InterruptedException { + Thread writerOne = new Thread(){ + public void run(){ + sharedObject.increamentCount(); + } + }; + writerOne.start(); + Thread.sleep(100); + + Thread writerTwo = new Thread(){ + public void run(){ + sharedObject.increamentCount(); + } + }; + writerTwo.start(); + Thread.sleep(100); + + Thread readerOne = new Thread(){ + public void run(){ + valueReadByThread2= sharedObject.getCount(); + } + }; + readerOne.start(); + + Thread readerTwo = new Thread(){ + public void run(){ + valueReadByThread3=sharedObject.getCount(); + } + }; + readerTwo.start(); + + assertEquals(2,valueReadByThread2); + assertEquals(2,valueReadByThread3); + + } + @After + public void cleanup(){ + sharedObject = null; + } +}