Illustrates the fact that Thread.stop() won't immediately stop a Thread which is waiting to acquire a lock

StopThreadWhileAcquiringLock.java

/**
This illustrates the fact that calling stop() on a Thread
won't stop the Thread if it's waiting on a monitor.

The output I get is:
  Thread t1 acquiring lock
  Thread t1 has lock
  Thread t2 acquiring lock
...waits forever...

If you remove t2.join(), you will find that t2 does in fact get stopped,
but only after t1 is stopped.

By contrast, if you stop/join t1 first, you get:
  Thread t1 acquiring lock
  Thread t1 has lock
  Thread t2 acquiring lock
  t1 alive? false
  t2 alive? false
*/
public class StopThreadWhileAcquiringLock {

  public static void main(String[] args) throws Exception {
    Runnable r = new Runnable() {
      @Override
      public void run() {
        System.out.println("Thread " + Thread.currentThread().getName() + " acquiring lock");
        acquireLock();
      }
    };
    Thread t1 = new Thread(r, "t1");
    Thread t2 = new Thread(r, "t2");
    
    t1.start();
    Thread.sleep(100);
    t2.start();    
    Thread.sleep(100);
    
    t2.stop();
    t2.join();

    t1.stop();
    t1.join();

    System.out.println("t1 alive? " + t1.isAlive());
    System.out.println("t2 alive? " + t2.isAlive());
  }

  public static synchronized void acquireLock() {
    System.out.println("Thread " + Thread.currentThread().getName() + " has lock");
    while (true) { }
  }

}