Multiple javaw.exe processes

Question

I've been working with Java on the Mac platform for quite a while now, but we've been noticing a Windows XP problem at work that is over my head:
"A javaw.exe process is launched each time I start the app. Quitting the program does not kill the javaw.exe process. After starting and quitting the app a number of times, my system's performace really starts to degrade. I have to manually kill all of the javaw.exe processes to liberate my RAM. "
Normally we open it just by double-clicking the jar file (since it has a manifest in it), but we've also resorted to using the console the open it. Nothing seems to make a difference.
I'm positive that System.exit(0) is being called after I save everything and close all my windows (I added console output to verify that).
Am I misusing System.exit()? Does anyone have any experience with this problem, or knowledge of the subject?

Answer 1

i don't believe that System.exit() is called. just
insert a Syste,.out.println() just before
System.exit() to check if it is really called.I already did. (That's why I said before "I'm positive it's called".)
This took days to hunt down, but today we finally figured it out (and a work-around):
The problem was a shutdown hook. (See Runtime.getRuntime().addShutdownHook(). )
I use them to save preferences, write an error log, and close up QuickTIme.
Apparently on Windows if you call QTSession.close() in a shutdown hook, the thread blocks. And any shutdown hook that blocks will keep the JVM from closing -- so if you're experience a similar problem check your shutdown hooks. And pray to the great computing gods in the sky that you're not using packages that abuse their own shutdown hooks.
I suspect the problem is that QuickTimeJava added its own shutdown hook, putting a synchronization lock on the ability to edit the current state of QTSessions. I say this because I could safely call: QTSession.isInitialized(), but QTSession.close() or QTSession.terminate() caused a deadlock.
The workaround:
My code now says:
MovieUtilities.shutdown();
System.exit(0);
where the method shutdown is simply:
//note that there might be several QTSession's open
while(QTSession.isInitialized()) {
     QTSession.close();
This keeps Windows machines from blocking, and the javaw.exe processes terminate normally.