JList bug? Or is it just me? Testers needed

Question

I have been having a minor but definitely irritating problem with an application I wrote. In several places I have 2 JList boxes inside JScrollPanes. Clicking on an item in the first list should instantly update the contents of the second. Most of the time it does just that. But it seems like 20% of the time my mouse click is ignored, or atleast the action is not acted on (the first list's item gets highlighted, but the second list does not update). It seems to either be OS or JDK version related as I created a simple test program and tried running it on a different OS with a different version (Solaris server with JDK 1.2.2), and there it worked fine. My system, which is where the problem occured uses Win2000 and I am using JDK 1.4.0. I tried reporting this bug to Sun but they wrote back and said they could not reproduce the bug.
Is there some weird glitch with just my PC? Or has anyone else ever seen anything like this? I will paste my test program code below. To use it, just keep selecting different items in the left-hand list and noting whether the contents of the right-hand list change to match. If you can do this about 20 times and they stay in sync, then it works fine for you. Otherwise please let me know! And if anyone can actualy help me prove to sun that this is a bug, or provide a fully-functional workaround I'll hand out some Duke Dollars.
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.awt.*;
* Used to test an aparent bug in JList or MouseAdapter
public class JListTest extends JFrame
   private Container    contentPane;
   private JScrollPane  scrollOne, scrollTwo;
   private JList        listOne, listTwo;
   private static final String[] listOneItems =
      {"Letters", "Pets", "Names", "Sports"};
   private static final String[] letterItems =
      {"A", "B", "C", "D", "E", "F", "G", "H"};
   private static final String[] petItems =
      {"Cat", "Dog", "Bird", "Fish", "Lizard", "Feret"};
   private static final String[] nameItems =
      {"Joe", "Bob", "Mike", "Sally", "Julie", "Mary", "Tony"};
   private static final String[] sportItems =
      {"Football", "Basketball", "Hockey", "Baseball", "Track & Field"};
   * Constructor
   public JListTest()
      super("JList Test");
      contentPane = this.getContentPane();
      contentPane.setLayout(new BorderLayout());
      listOne = new JList();
      listTwo = new JList();
      listOne.setFixedCellWidth(200);
      listTwo.setFixedCellWidth(200);
      scrollOne = new JScrollPane(listOne,
               JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
               JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
      scrollTwo = new JScrollPane(listTwo,
               JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
               JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
      listOne.setListData(listOneItems);
      contentPane.add(scrollOne, BorderLayout.WEST);
      contentPane.add(scrollTwo, BorderLayout.EAST);
      this.setResizable(true);
      addEventHandlers();
      this.setLocation(100,40);
      this.pack();
      this.setVisible(true);
   private void addEventHandlers()
      listOne.addMouseListener(new MouseAdapter()
         public void mouseClicked(MouseEvent e)
            handleMouseClicks(e);
      // Handles clicking on the window's "x" button to close it
      this.addWindowListener(new WindowAdapter()
         public void windowClosing(WindowEvent e)
            System.exit(1);
   protected void handleMouseClicks(MouseEvent e)
      int listIndex = listOne.getSelectedIndex();
      if (listIndex == 0)
         listTwo.setListData(letterItems);
      else if (listIndex == 1)
         listTwo.setListData(petItems);
      else if (listIndex == 2)
         listTwo.setListData(nameItems);
      else if (listIndex == 3)
         listTwo.setListData(sportItems);
   public static void main(String[] args)
      JListTest jListTest = new JListTest();
}

Answer 1

I am not able to reproduce what you have seen, but have you tried using a ListSelectionListener in place of your MouseListener?
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.awt.*;
/*** Used to test an aparent bug in JList or MouseAdapter*/
public class JListTest
    extends JFrame
    private              Container   contentPane;
    private              JScrollPane scrollOne, scrollTwo;
    private              JList       listOne, listTwo;
    private static final String[]    listOneItems = {"Letters", "Pets", "Names", "Sports"};
    private static final String[]    letterItems  = {"A", "B", "C", "D", "E", "F", "G", "H"};
    private static final String[]    petItems     = {"Cat", "Dog", "Bird", "Fish", "Lizard", "Feret"};
    private static final String[]    nameItems    = {"Joe", "Bob", "Mike", "Sally", "Julie", "Mary", "Tony"};
    private static final String[]    sportItems   = {"Football", "Basketball", "Hockey", "Baseball", "Track & Field"};
    /**   * Constructor   */
    public JListTest()
        super("JList Test");
        contentPane = this.getContentPane();
        contentPane.setLayout(new BorderLayout());
        listOne = new JList();
        listOne.setFixedCellWidth(200);
        listOne.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); // <------------------------------<<<
        listTwo = new JList();
        listTwo.setFixedCellWidth(200);
        scrollOne = new JScrollPane( listOne,
                                     JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                                     JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
        scrollTwo = new JScrollPane( listTwo,
                                     JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                                     JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
        listOne.setListData(listOneItems);
        contentPane.add(scrollOne, BorderLayout.WEST);
        contentPane.add(scrollTwo, BorderLayout.EAST);
        this.setResizable(true);
        addEventHandlers();
        this.setLocation(100,40);
        this.pack();
        this.setVisible(true);
    private void addEventHandlers()
        listOne.addListSelectionListener( // <------------------------------<<<
            new ListSelectionListener() {
                public void valueChanged(ListSelectionEvent e)
                    if ( ! e.getValueIsAdjusting()) { // <------------------------------<<<
                        handleListSelection();
        // Handles clicking on the window's "x" button to close it
        this.addWindowListener(
            new WindowAdapter() {
                public void windowClosing(WindowEvent e)
                    System.exit(1);
    protected void handleListSelection() // <------------------------------<<<
        int listIndex = listOne.getSelectedIndex();
        if (listIndex == 0) {
            listTwo.setListData(letterItems);
        } else if (listIndex == 1) {
            listTwo.setListData(petItems);
        } else if (listIndex == 2) {
            listTwo.setListData(nameItems);
        } else if (listIndex == 3) {
            listTwo.setListData(sportItems);
    public static void main(String[] args)
        JListTest jListTest = new JListTest();
}