POGO.com report a memory regression in 5u8.   Run a few simple applets (or the applet supplied from pogo) in the same browser, and then navigate the browser to a page without any applet.  Perform GC.

If you hook up JProfiler, you will still see instances of AppletViewer and IExplorerEmbedded frame there, with a JNI Gloal Ref referenceing it, preventing it from GC.

JProfiler screenshot:
http://javaweb.sfbay.sun.com/~ngthomas/pogo/applet-jni-ref.PNG

Pogo.com simple applet source:
import java.applet.Applet;

public class JNIGlobalReferenceLeakDemoApplet extends Applet {
    private int[] mBigLeak;

    public void init() {
        mBigLeak = new int[1000000];
        for (int i = 0; i < mBigLeak.length; i++) {
            mBigLeak[i] = i;
        }
    }
}

With 5u7, the problem cannot be reproduced.

Also, if I replace awt.dll and rt.jar from 5u7 to 5u8, I cannot reproduce the problem too.  So I am assigning the bug to awt so they can take a look.