Browser gets closed abruptly producing 'Program Error' on launched browser

Question

Hi all,
I have a applet program (code copied below). The applet just launches a test frame. The applet is launched by clicking on a 'launch' button in a browser(either Netscape or Mozilla).
When user closes the frame by clicking on frame close icon, the applet's stop() is invoked. In applet's stop, there are some system resource cleaning code and code for closing the applet window.
But when user closes the frame, and before applet window gets closed, if user again clicks on 'launch' button in the parent browser, the whole browser gets closed abruptly producing a Program Error saying 'Netscp.exe has generated errors and will be closed by windows. You will need to restart the program' in case of netscape browser. The same happens for mozilla browser too.
what is the problem here?
how to fix it...
please help...
-thx,
Soni.
(To execute this plugin.jar of jdk is required)
import javax.swing.JApplet;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import netscape.javascript.JSObject;
public class SampleApplet extends JApplet implements ActionListener{
     protected JButton closeButton = null;
     protected JSObject win = null;
     private JFrame frame = null;
     public void init(){
          this.win = JSObject.getWindow(this);
          this.closeButton = new JButton("Close Browser Window");
          //this.add(this.closeButton);
          //this.closeButton.addActionListener(this);
          frame = new JFrame("Test Frame");
          frame.setSize(300, 400);
          frame.addWindowListener(new WindowAdapter() {
               public void windowClosing(WindowEvent e) {
System.out.println("windowClosing");
                    SampleApplet.this.stop();
          frame.show();
     } // ends init(void)
     public void actionPerformed(ActionEvent ae){
          //this.win.eval("self.close();");
          //closeLaunchedBrowser();
          stop();
     private boolean alreadyClosed = false;
     public void stop() {
          if (!alreadyClosed) {
               alreadyClosed = true;
               closeLaunchedBrowser();
               frame.dispose();
               System.gc();
               System.runFinalization();
     private void closeLaunchedBrowser() {
          final SampleApplet thisObject = this;
          Runnable r = new Runnable() {
               public void run() {
                    try {
                         JSObject win = (JSObject)JSObject.getWindow(thisObject);
                         if (win != null && win.toString() != null) {
                              //win.eval("top.opener=self;self.close();");
                              //win.call("close", null);
                              win.eval("self.close();");
                    } catch (Exception e) {
          Thread t = new Thread(r);
          t.start();
} // ends class CloseApplet
//////////////////////////////////////////////////////

Answer 1

not at all since it only causes problems.
It works relativly stable on IE (since its an very old browser not updated since a long time -> SUN was able to work arround all the open IE bugs) but all other browsers cause troubles, call it opera, safari, konqueror or all the others.
The problem is that the plugin-interface requires a lot of interaction between the jvm and the browser and since browsers change very often it seems almost impossible to guarantee compatibility.
Sometimes it works, sometimes not, sometimes its just broken in one version and works in an older one.
I would suggest to stay away from java->javascript or the other was round...
lg Clemens