How do you free memory when applet ends?

Question

I have an applet that uses 4 jframes. Any of the frames are set to call both stop() and destroy() whenever user clicks "Exit" or "X" in upper right corner of a frame.
The applet destroy() method does the following:
myAOS32001Frame = null;
myAOS32002Frame = null;
myAOS32003Frame = null;
myAOS32004Frame = null;
myMemoryChangeThread.stop();
try {
URL endedURL = new URL(this.getCodeBase(), "AOS320acEnded.html");
this.getAppletContext().showDocument(endedURL);
} // try
catch (MalformedURLException urlexc) {
urlexc.printStackTrace();
} // catch
This doesn't free up any memory at all. Only when the user closes the browser altogether does the memory free up.
Do I have to set EVERY object (those within frames) to null? How do I set the main applet object (the JApplet class instance) to null (not just its child frames)? Should the garbage collector be run one last time? In what order should all these things occur?
If every object needs to be set to null, anybody have a nice tidbit of code that loops through array of components (and properties) or something and sets them to null?
Thanks.

Answer 1

Thank you both for the tips. They were helpful.
Now my mission is to make the applet as small as possible. It appears the base JVM occupies about 18MB of memory initially, and then my applet uses 12MB more (at times), and the JVM "reserves" about 10MB more.
The only part under my control is the 12MB, it appears, and I'd be interested in general tips to make that as small as possible (maybe by using certain variable types instead of ones currently used, etc.). But I'll ask that in a different thread.