Name: clC74495 Date: 04/09/99


This bug report is from Oracle, a Java licensee.
It occurs in JDK1.1.7B. The Oracle bug number is 868559.

While looking for memory leaks, we found some "LightweightDispatcher"
objects were leaking. LightweightDispatcher is defined in
java/awt/Container.java. We found that in trackMouseEnterExit the method
startListeningForOtherDrags is called. This does a
Toolkit.getEventQueue().addEventQueueListener(this). The method
stopListeningForOtherDrags (which does the corresponding removeListener)
is only called if trackMouseEnterExit gets a MOUSE_EXITED event. It looks
like sometimes that never happens, and so the LightweightDispatcher, as long
and any objects it refers to, will never get GC'ed. This seems to happen
a lot if you wiggle the mouse over a window when it's disappearing.

The following code fixes the problem:

[in LightweightDispatcher.removeNotify(), just before "super.removeNotify();"]
    if (dispatcher != null ) {
        Toolkit.getEventQueue().removeEventQueueListener(dispatcher);
        dispatcher = null;
    }
[end]

An alternative is to remove the "private" from the definition of
stopListeningForOtherDrags, and to call that instead of calling
removeEventQueueListener directly.
(Review ID: 56783)
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