Icon corruption and loss of sound?

Question

I wrote a messenging application in java, think of it like a glorified version of WinPopUp or something similar. Anyway, when it is loaded on a Win2k/XP system (haven't tried it on other operating systems), it appears to be working perfectly until you leave your computer for an extended period of time. You lock the workstation, and come back a few hours later. What I have noticed is when I come back to my station and unlock it, the icons on the application are often corrupted. To try and fix this, I added repaint() calls to JFrame.windowActivated(). Doesn't help. I also noticed that after locking the workstation and coming back a few hours later, that occationally the sound effects stop working for no reason that I can explain. My sound code is rather straight forward:
public void playSound(String s) {
InputStream iStream = null;
AudioStream aStream = null;
try {
iStream = new FileInputStream(s);
aStream = new AudioStream(iStream);
catch (Exception e) { System.err.println(e.toString()); }
AudioPlayer.player.start(aStream);
If I close the application and reload it, the problem goes away. To make matters more confusing, is after the program displays corruption, if you lock the workstation and leave for a few hours and come back, the corruption you witnessed earlier may have gone away. I'm very confused. Has anyone else had this sort of problem or have any suggestions as to fix it?
I'm running and developing with the Java SDK 1.4.1 on a Windows XP Pro box...

Answer 1

Sifted through the bug database -- didn't find anything applicable. Still have to finish looking through it however. As for unloading the graphics and audio data...
Perhaps I have a misunderstanding of how java handles function calls, but the only Audio streams or mention of the AudioPlayer class that exist in my program are handled by the playSound function (above). Since they are local to that method, they shouldn't exist outside that function, and thus Java's garbage collection should be unloading the data when the function call is finished. I suppose I can try and force that by setting all the variables in the method to null when I'm done, but that seems like a waste of typing (although admittedly, at this point I'll try anything). That function takes a string which points to the location of the .wav I want to play... and since the strings are constants I know they aren't changing somehow during execution... shrug.
As for the graphics idea... I suppose I can set my ImageIcon variables to alternate copies of the same graphics every now and again to "reload" it, but what I'm really shooting for is either A) I'm doing something wrong, with ideas on how to fix it, or B) this is a known bug that will miraculously fix itself once Sun gets around to fixing the JVM.