Name: viR10068 Date: 03/20/2003


The TreadGroup.destroy() method does not destroy the non-active subgroup.
But the specification says:
"Destroys this thread group and all of its subgroups."

See the source and execution log for details.

Source:
----------------------- B.java ------------------------------

import java.io.PrintStream;

class Bt extends Thread {
    B event;

    Bt(Bg group, B event) {
        super(group, group.groupName + ".activeThrd");
        this.event = event;
    }

    public void run() {
        event.run();
    }
} // end class Bt


class Bg extends ThreadGroup {

    String groupName;
    Thread activeThrd;
    B event;

    void finish() throws InterruptedException {
        activeThrd.join();
    }

    Bg(ThreadGroup parent, B event) {
        super("Bg_");
        this.event = event;
        groupName = "Bg_";
        activeThrd = new Bt(this, event);
        activeThrd.start();
    }

} // end class Bg

public class B {

    boolean end = false;

    public synchronized void run() {
        while (!end) {
            try {
                wait();
            } catch (InterruptedException e) {
            }
        }
    }

    public synchronized void stopAll() {
        end = true;
        notifyAll();
    }

    public int run(String argv[], PrintStream out) {

        Bg group = new Bg(Thread.currentThread().getThreadGroup(), this);
        Bg cgroup = new Bg(group, this);

        try {
            stopAll();
            group.finish();
            cgroup.finish();
        } catch (InterruptedException e) {
            out.println("InterruptedException while joining child thread.");
            return 2;
        }

        try {
            group.destroy();
        } catch (Throwable e) {
            out.println("unexpected exception:" + e);
            return 2;
        }

        if (!group.isDestroyed()) {
            out.println("destroy() called but group !isDestroyed()");
            return 2;
        }
        out.println("OK: destroy() called and 'group' isDestroyed()");
        if (!cgroup.isDestroyed()) {
            out.println("destroy() called but 'cgroup' !isDestroyed()");
            return 2;
        }

        out.println("OK: destroy() called and 'cgroup' isDestroyed()");
        return 0;
    }

    public static void main(String args[]) {
        (new B()).run(args, System.out);
    }
}
-------------------------------------------------------------
Execution log:
% /jdk1.5.0/solaris-sparc/bin/java -showversion B
java version "1.5.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta-b02)
Java HotSpot(TM) Client VM (build 1.5.0-beta-b02, mixed mode)

OK: destroy() called and 'group' isDestroyed()
destroy() called but 'cgroup' !isDestroyed()
% java -showversion B
java version "1.4.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-b21)
Java HotSpot(TM) Client VM (build 1.4.1-b21, mixed mode)

OK: destroy() called and 'group' isDestroyed()
destroy() called but 'cgroup' !isDestroyed()
%

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