ExecutorService and FutureTask - Blocked Thread

[Rafael F. Oliveira]

Hi,

I have the following code:

		 
...
	private static ScheduledExecutorService executor = Executors.newScheduledThreadPool(10);
...

final Future<Boolean> future = executor.submit(new Callable<Boolean>() {
				public Boolean call() {
					try {						
						return MyClass.nativeMethod();
					} catch (Exception e) {
						// TODO Auto-generated catch block
					}
					return false;
				}
			});
...
		 executor.schedule(new Runnable(){			 
		     public void run(){
		    	 future.cancel(true);
		     }      
		 }, 5000, TimeUnit.MILLISECONDS);

I'm running the aforementioned code inside a servlet container (tomcat).

The native method calls a Delphi method that executes a "showMessage", when the futureTask is running the native method calls the showMessage (it will just wait for the user to press "OK"), because it executes inside a servlet, the user doesn't see the dialog message, so, the task will run until the timeout.

The problem is that my task stops, but the thread (pool-1-thread-1) doesn't stop.

In that case, how can I kill a thread?

Thanks in advance.

[Mike Simmons]

If the thread is part of the thread pool in an ExecutorService, the best way is probably to call shutdown() on the ExecutorService.

Alternately, if you aren't yet ready to shut down the whole ExecutorService, you don't really need to stop the thread. It can just wait until the ExecutorService is given a new task that it can work on. Or until shutdown() is called.

[Rafael F. Oliveira]

My native method is synchronized and "showMessage" is called in some cases...if the thread isn't stopped or killed new tasks will start in a blocked mode. Because that I would like to kill a specific thread instead of all of them when the timeout is exceeded. Is it possible?

I can get the thread by use the following code:

...  
    private static ScheduledExecutorService executor = Executors.newScheduledThreadPool(10);  
    final MyThread myThread = new MyThread();
...  
  
final Future<Boolean> future = executor.submit(new Callable<Boolean>() {  
                public Boolean call() {  
                    try {                                    
                        myThread.value = Thread.currentThread();  // getting the Thread
                        return MyClass.nativeMethod();  
                    } catch (Exception e) {  
                    }  
                    return false;  
                }  
            });  
...  
         executor.schedule(new Runnable(){             
             public void run(){  
                 System.out.println(myThread.value);    // It shows and cancels the blocked thread
                 future.cancel(true);  
             }        
         }, 5000, TimeUnit.MILLISECONDS
...
class MyThread{
Thread value;
}