java.lang.Thread.stop() hangs when stopping a blocked thread

Name: akC45999 Date: 11/27/96


 Two threads aquire their own monitors and then thats of each other,
so deadlock occurs. The third thread attempts to stop them
and hangs itself.


-------------------------- t_0.java ------------------------------
interface t_0 {

 public void aquire_self ();
 public void aquire_peer ();

}

-------------------------- invokeinterface02301.java ------------------------------
public class invokeinterface02301 extends Thread implements t_0 {

  t_0 t;

  static java.io.PrintStream out;

  public static void trace (String msg) {
out.println(Thread.currentThread().getName()+": "+msg);
  }

  public void run () {
trace("attempt to aquire_self");
aquire_self();
  }

  public synchronized void aquire_self () {
trace("self aquired");
try {
sleep(100);
} catch (InterruptedException e) {
out.println("InterruptedException:");
}
trace("attempt to aquire_peer:"+t);
t.aquire_peer();
  }

  public synchronized void aquire_peer () {
trace("peer aquired");
  }

  public static int run (String argv[], java.io.PrintStream out_p)
  {
out=out_p;
invokeinterface02301
th1=new invokeinterface02301()
,th2=new invokeinterface02301()
;
th1.t=th2;
th1.setName("thr 1");
th2.t=th1;
th2.setName("thr 2");
th1.start();
th2.start();
try {
sleep(300);
} catch (InterruptedException e) {
out.println("InterruptedException:");
}
trace("game over");
int res=2;
if (th1.isAlive()) {
trace("th1 isAlive");
th1.stop();
trace("th1 stopped");
res--;
}
if (th2.isAlive()) {
trace("th2 isAlive");
th2.stop();
trace("th2 stopped");
res--;
}
if (res==1) {
out.println("something wrong");
res=2;
}
return res;
  }

  public static void main(String argv[])
  {
     System.exit(run(argv,System.out));
  }

}
----------------------- output ----------------------------------
thr 1: attempt to aquire_self
thr 1: self aquired
thr 2: attempt to aquire_self
thr 2: self aquired
thr 1: attempt to aquire_peer:Thread[thr 2,5,main]
thr 2: attempt to aquire_peer:Thread[thr 1,5,main]
main: game over
main: th1 isAlive

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