FULL PRODUCT VERSION :
vm_info: Java HotSpot(TM) Client VM (1.6.0_01-b06) for windows-x86, built on Mar 14 2007 00:24:02 by "java_re" with unknown MS VC++:1310

FULL OS VERSION :
ver: Windows XP Build 2600 Service Pack 2

EXTRA RELEVANT SYSTEM CONFIGURATION :
INTERNET EXPLORER 6.0.2900.2180.xpsp_sp2.qfe.070227-0300
OS: Windows XP Build 2600 Service Pack 2
CPU:total 2 family 6, cmov, cx8, fxsr, mmx, sse, sse2
Memory: 4k page, physical 2096300k(938668k free), swap 4037840k(3032392k free)
vm_info: Java HotSpot(TM) Client VM (1.6.0_01-b06) for windows-x86, built on Mar 14 2007 00:24:02 by "java_re" with unknown MS VC++:1310


A DESCRIPTION OF THE PROBLEM :
IE/JVM gets destabilized when a Java applet modifies browser DOM. The browser crashes after the applet code is run and page reload is invoked. Crashing has been however observed also randomly without page reloads required (less frequently).

I'm providing the source code lower; NetBeans project, test HTML page and the applet jar can be found here:
http://wiki.netbeans.org/wiki/attach/JK_ScratchPad/CrashIEApplet.zip
http://wiki.netbeans.org/wiki/attach/JK_ScratchPad/index.html
http://wiki.netbeans.org/wiki/attach/JK_ScratchPad/CrashIEApplet.jar

As for the source code - crash occurs if the code is executed in the Applet's start method, in a public method invoked from the browser upon a HTML button click and even if the code is executed in a separate Java thread.

THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: Did not try

THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Did not try

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the applet (you may want to use the attached index.html).
Hit the 'say hello' button. Refresh the page. Try a couple times. IE crashes.

EXPECTED VERSUS ACTUAL BEHAVIOR :
IE should not crash.
ERROR MESSAGES/STACK TRACES THAT OCCUR :
See Attachment (hs_err_pid.log)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package test;

import netscape.javascript.JSObject;

/**
 *
 * @author Jiri Kopsa
 */
public class CrashIEApplet extends javax.swing.JApplet {
    
    public void printHello() {
        
        new Thread(new Runnable(){
            public void run(){
                for (int i=0; i < 20; i++) {
                    JSObject win = getWindow();
                    JSObject document = (JSObject) win.getMember("document");
                    JSObject jso = (JSObject) document.call("createElement",new String[]{"div"});
                    jso.setMember("innerHTML", "Hello <b>world</b>!");
                    JSObject body = (JSObject) document.getMember("body");
                    body.call("appendChild", new Object[]{jso});
                }
            }
        }).start();
    }
    
    public JSObject getWindow(){
        return (JSObject) JSObject.getWindow(this);
    }
    
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
None known.