isInterrupted() method vs interrupted() method

[kiran madhan]

I know basically what these methods do...! But when I run the following programming it is giving result and that confused me a lot.

first i will post code:

//interrupting thread not in sleep or waiting state...!

class TestInterruptingThread2 extends Thread
{  
public void run()
{  
for(long i=1;i<=100;i++)
{
System.out.println("doing task....: "+i);  
}
} 
public void show()
{
for(long i=1;i<=100;i++)
{
System.out.println("in show....: "+i);  
}
} 
  
public static void main(String args[])throws InterruptedException
{
TestInterruptingThread2 t1=new TestInterruptingThread2();  
	t1.start();  
System.out.println("is thread interrupted..:"+t1.isInterrupted());
       	t1.interrupt();  
System.out.println("is thread interrupted..:"+t1.interrupted());
System.out.println("is thread interrupted..:"+t1.isInterrupted());

/*   if(t1.isInterrupted()==true)
	{
	t1.show();
	}*/
}    
}

In the above program , after thread interruption for the below code, I am getting output as: false & true.

-------------------------------------------------------------------------------------------------------------------
      t1.interrupt();  
System.out.println("is thread interrupted..:"+t1.interrupted());
System.out.println("is thread interrupted..:"+t1.isInterrupted());

----------------------------------------------------------------------------------------------------------------

My question is, after interruption how the interrupted() method giving result as false
but isInterrupted() method is giving result as true.....?


Please help me in this...?

thanks in advance...!

[Jesper de Jong]

Welcome to the Ranch. Have you looked at the API documentation of the methods in class Thread? It explains the difference.

The documentation for interrupted() states:

Tests whether the current thread has been interrupted. The interrupted status of the thread is cleared by this method.

And the documentation for isInterrupted() states:

Tests whether this thread has been interrupted. The interrupted status of the thread is unaffected by this method.

So, the interrupted() method tells you if the thread is interrupted, but also clears the interrupted status of the thread. The isInterrupted() method just tells you if the thread is interrupted, but does not change the interrupted status of the thread.

Also, very important: the interrupted() method is a static method. It does not check if the thread you are calling it on is interrupted, but if the current thread is interrupted. A call like t1.interrupted() is misleading - it does not check if thread t1 is interrupted, but if the main thread is interrupted!

[kiran madhan]

oh..! Thanks a lot ...! I understood what was my mistake...thanks a lot...Jesper de Jong..!