Garbage collection notification?

Question

I\'d like to register a callback with the JVM so I know when garbage collection is happening. Is there any way to do this?

EDIT: I want to do this so I can log out

Answer 1

Java code sample using the GarbageCollectorMXBean referred to in the accepted answer:

static
{
    // notification listener. is notified whenever a gc finishes.
    NotificationListener notificationListener = new NotificationListener()
    {
        @Override
        public void handleNotification(Notification notification,Object handback)
        {
            if (notification.getType().equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION))
            {
                // extract garbage collection information from notification.
                GarbageCollectionNotificationInfo gcInfo = GarbageCollectionNotificationInfo.from((CompositeData) notification.getUserData());

                // access garbage collection information...
            }
        }
    };

    // register our listener with all gc beans
    for (GarbageCollectorMXBean gcBean : ManagementFactory.getGarbageCollectorMXBeans())
    {
        NotificationEmitter emitter = (NotificationEmitter) gcBean;
        emitter.addNotificationListener(notificationListener,null,null);
    }
}

site that has detailed sample code that uses the GarbageCollectorMXBean.