Question

I have two classes. In class A, I have the run() method looped forever, while in the class B, i have the threadpool.

My question is, From Class B, how can I control and stop the thread executing run() method in class A , I have tried forceshutdown, threadExecutor.shutdownNow(), But it isnt working.
The loop seems to go on forever.

Here is example piece of code:

---

public class A implements Runnable {
    public void run() {
        while (true) {
            System.out.println("Hi");
        }
    }
}

---

public class B {
    public static void main(String[] args) {
        int noOfThreads = 1;
        A ThreadTaskOne = new A();
        System.out.println("Threads are being started from Class B");
        ExecutorService threadExecutor = Executors.newFixedThreadPool(noOfThreads);
        threadExecutor.execute(ThreadTaskOne);
        threadExecutor.shutdownNow();
        System.out.println("B Ends, no of threads that are alive : " + Thread.activeCount());
    }
}

Answer 1

As @MadProgammer said, your “infinite” loop needs to pay attention to Thread.isInterrupted. e.g. (very schematic)

public void run() {

   while (!Thread.isInterrupted()) {
      doSomethinginTheLoop1();
      blah...blah...blah
      // if the loop is very long you might want to check isInterrupted 
      // multiple times for quicker termination response
      doSomethingInTheLoop2();
   }

   // now, here's a decision of what you do
   // do you throw an InterruptedException or trust others to check interrupted flag.
   // read Java COncurrency in Practice or similar...
}