Odtnhj

public class WaitNotifyAll 
 private static volatile Object resourceA = new Object();

 public static void main(String args) throws Exception 
 Thread threadA = new Thread(new Runnable() 
 @Override
 public void run() 
 synchronized (resourceA) 
 try 
 System.out.println("threadA begin wait");
 resourceA.wait();
 System.out.println("threadA end wait");
 catch (InterruptedException e) 
 e.printStackTrace();
 
 
 
 );

 Thread threaB = new Thread(new Runnable() 
 @Override
 public void run() 
 synchronized (resourceA) 
 System.out.println("threadC begin notify");
 threadA.interrupt();
 resourceA.notify();
 
 
 );

 threadA.start();

 Thread.sleep(1000);

 threaB.start();

 System.out.println("main over");
 
 

There are two possible result here：

1. throws InterruptedException




2. normal termination

why?

I don't understand. when threadA is interruptted ,result should throws InterruptedException. but sometimes execute this program, it can normal finish.

environment： java8， mac

Because of reordering. In normal termination compiler reordered instruction interrupt and notify, interruption invokes on working thread and no interrupted exception throws.
Try to forbid reordering with reading volatile variable and you always get interrupted exception.

public class WaitNotifyAll 
private static volatile Object resourceA = new Object();

public static void main(String args) throws Exception 
 Thread threadA = new Thread(new Runnable() 
 @Override
 public void run() 
 synchronized (resourceA) 
 try 
 System.out.println("threadA begin wait");
 resourceA.wait();
 System.out.println("threadA end wait");
 catch (InterruptedException e) 
 e.printStackTrace();
 
 
 
 );

 Thread threaB = new Thread(new Runnable() 
 @Override
 public void run() 
 synchronized (resourceA) 
 System.out.println("threadC begin notify");
 threadA.interrupt();
 System.out.print(resourceA);
 resourceA.notify();
 
 
 );

 threadA.start();

 Thread.sleep(1000);

 threaB.start();

 System.out.println("main over");

When a thread receives both an interrupt and a notify, the behaviour may vary.

Please refer to https://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html#jls-17.2.3

Credit - Alex Otenko on the Concurrency Interest mailing list