Hi,

the Hotspot crashes when a JVMTI agent tries to get all loaded classes
triggered by a thread stop event and that dying thread has an async
exception pending. You can reproduce the problem with the following
small program:

public class AsynchronousExceptionTest {
    public static void main(String[] args) {
        while (true) {
            final Thread t1 = new Thread(new Runnable() {
                public void run() {
                    try {
                        Thread.sleep((int) (Math.random() * 100));
                    } catch (InterruptedException e) {
                        // Ignore.
                    }

                    System.gc();
                }
            });

            Thread t2 = new Thread(new Runnable() {
                public void run() {
                    try {
                        Thread.sleep((int) (Math.random() * 100));
                        t1.stop();
                    } catch (InterruptedException e) {
                        // Ignore.
                    }
                }
            });

            t1.start();
            t2.start();

            try {
                t1.join();
                t2.join();
            } catch (InterruptedException e) {
                // Ignore.
            }
        }
    }
}

and starting the VM with the following commandline:
java -agentlib:jdwp=transport=dt_socket,server=y,address=8000,suspend=n AsynchronousExceptionTest