}
        catch (NumberFormatException nfex)
        {
            trace.Print("Invalid port number (" + tfPort.getText() + ")");
            return;
        }
        trace.Print("Connecting to " + host + ":" + port);

        CommMgr cm = new CommMgr
            (ESConstants.ES_USERID,
             ESConstants.ES_PASSWORD,
             ESApplet.ES_PCMGR_HOST,
             ESApplet.ES_PCMGR_PORT,
             ESConstants.ES_PCMGR_TIMEOUT,
             ESConstants.ES_UNIX_TIMEOUT
             );
        cm.ConnectPCMgr(tfHost.getText(),port);

    }

    //----------------------------------
    // Print
    //----------------------------------
    static synchronized public void
    Print(String msg, int level)
    {
        if (trace == null)
        {
            trace = Create();
        }
        if (level <= filterLevel)
        {
            trace.Trace(msg);
        }
    }

    //----------------------------------
    // Print
    //----------------------------------
    static synchronized public void
    Print(Exception ex)
    {
        //NOTE: exceptions are NEVER filtered!
        if (trace == null)
        { trace = Create();
        }
        trace.Trace("********** EXCEPTION **********");
        trace.Trace("===> " + ex.getClass().getName());
        trace.Trace("===> " + ex);
        trace.Trace("===> " + ex.getMessage());
        trace.Trace("*******************************");
        System.out.println("********** EXCEPTION **********");
        System.out.println("===> " + ex.getClass().getName());
        System.out.println("===> " + ex);
        System.out.println("===> " + ex.getMessage());
        ex.printStackTrace();
        System.out.println("*******************************");
    }

    //----------------
    // SetFilterLevel
    //----------------
    /*
    public void
    SetFilterLevel(int i)
    {
        filterLevel = i;
    }
    */

    //----------------------------------
    // Show
    //----------------------------------
    static synchronized public void
    Show()
    {
        if (trace == null)
        {
            trace = Create();
        }
        trace.setVisible(true);

        java.awt.Toolkit theToolkit = java.awt.Toolkit.getDefaultToolkit();
        java.awt.Dimension d = theToolkit.getScreenSize();
        trace.setLocation(d.width-trace.getSize().width,0);
    }

    //----------------------------------
    // Trace
    //----------------------------------
    public synchronized void
    Trace(String msg)
    {
        if (cbCapture.isSelected() == false)
        {
            return;
        }
        //ta.append("[" + Thread.currentThread().getName() + "] " + msg + "\n");
        ta.append(msg + "\n");
    }

    //----------------------------------
    // CEEChangeListener
    //----------------------------------
class CEEChangeListener implements com.sun.java.swing.event.ChangeListener
{
public void stateChanged(ChangeEvent event)
{
Object object = event.getSource();
if (object == theSlider)
{
     filterLevel = theSlider.getValue();
     lblLevel.setText(GetFilterLevelString());
}
}
}

    //----------------------------------
    // CEEActionListener
    //----------------------------------
class CEEActionListener implements java.awt.event.ActionListener
{
public void actionPerformed(java.awt.event.ActionEvent event)
{ Object object = event.getSource();
if (object == btnClear)
{ ta.setText("");
}
else if (object == btnGetServerTime)
{ GetServerTime();
}
else if (object == btnCopy)
{ OnCopy();
}
else if (object == btnDirect)
{ OnDirect();
}
else if (object == btnPCMgr)
{ OnPCMgr();
}
}
}

    //----------------------------------
    // CEEItemListener
    //----------------------------------
class CEEItemListener implements java.awt.event.ItemListener
{
public void itemStateChanged(java.awt.event.ItemEvent event)
{
Object object = event.getSource();
//if (object == cbShowReceivedData)
//{ showReceivedData = cbShowReceivedData.isSelected();
//}
}
}

    //----------------------------------
    // CEEWindowAdapter
    //----------------------------------
class CEEWindowAdapter extends java.awt.event.WindowAdapter
{
public void windowClosing(java.awt.event.WindowEvent event)
{ Object object = event.getSource();
if (object == DebugTrace.this)
{ setVisible(false);
}
}
}

}




The code works fine when I use Swing 1.0.1 with JDK 1.1.5 and JDK 1.1.6. However, the failure appears with Swing 1.0.2
on both JDK 1.1.5 and JDK 1.1.6.

My console output and backtrace are:

H:\prog\jescat\brad>java -classpath c:\swing102\swingall.jar;c:\jdk116\lib\classes.zip;h:\prog\jescat\brad auiarch.util.Debug
Trace
Exception occurred during event dispatching:
java.lang.NullPointerException
        at com.sun.java.swing.ToolTipManager$JPanelPopup.show(ToolTipManager.java:449)
        at com.sun.java.swing.ToolTipManager.showTipWindow(ToolTipManager.java:169)
        at com.sun.java.swing.ToolTipManager$insideTimerAction.actionPerformed(ToolTipManager.java:358)
        at com.sun.java.swing.Timer.fireActionPerformed(Compiled Code)
        at com.sun.java.swing.Timer$DoPostEvent.run(Timer.java:100)
        at com.sun.java.swing.SystemEventQueueUtilities.processRunnableEvent(Compiled Code)
        at com.sun.java.swing.SystemEventQueueUtilities$RunnableTarget.processEvent(Compiled Code)
        at java.awt.Component.dispatchEventImpl(Compiled Code)
        at java.awt.EventDispatchThread.run(Compiled Code)

Full thread dump:
    "TimerQueue" (TID:0xf8d7f8, sys_thread_t:0x8bc250, Win32ID:0xa9, state:CW) prio=5
        com.sun.java.swing.TimerQueue.run(Compiled Code)
    "AWT-Windows" (TID:0xf863a0, sys_thread_t:0x8ac280, Win32ID:0xc0, state:R) prio=5
        sun.awt.windows.WToolkit.run(WToolkit.java:107)
        java.lang.Thread.run(Compiled Code)
    "AWT-EventQueue-0" (TID:0xf86458, sys_thread_t:0x8ac170, Win32ID:0xca, state:CW) prio=5
        java.lang.Object.wait(Compiled Code)
    "Finalizer thread" (TID:0xf80088, sys_thread_t:0x893560, Win32ID:0xcd, state:CW) prio=2
    "main" (TID:0xf800b0, sys_thread_t:0x890350, Win32ID:0xbe, state:CW) prio=5
Monitor Cache Dump:
    java.awt.EventQueue@F861E0/FD96C0: <unowned>
        Waiters: 1
    com.sun.java.swing.TimerQueue@F8D800/FFB2F0: <unowned>
        Waiters: 1
Registered Monitor Dump:
    SymcJIT Method Monitor: <unowned>
    SymcJIT Method Monitor: <unowned>
    SymcJIT Method List Monitor: <unowned>
    SymcJIT Fixups Allocation: <unowned>
    SymcJIT Code Allocation: <unowned>
    SymcJIT Data Allocation: <unowned>
    Thread queue lock: <unowned>
        Waiters: 1
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
        Waiters: 1
    Monitor registry: <unowned>
(Review ID: 29802)
======================================================================


Name: rk38400 Date: 05/06/98


To reproduce: I simply wait for a tool tip to appear when I position the mouse over a text field or button.

Source code:
package auiarch.util;

import com.sun.java.swing.*;
import com.sun.java.swing.event.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.io.*;
import java.net.*;
import java.util.Vector;

import auiarch.comm.*;
import auiarch.applet.*;

import com.sun.java.swing.JButton;
import com.sun.java.swing.JCheckBox;
import com.sun.java.swing.JTextArea;
import com.sun.java.swing.JTextField;
import com.sun.java.swing.JLabel;
import com.sun.java.swing.JSlider;

public class
DebugTrace extends Frame implements ClipboardOwner
{
public static void main(String[] args)
{
(new DebugTrace()).show();
}

    //----------------------------------
    // Static data
    //----------------------------------
    static int filterLevel = ESConstants.DEFAULT_FILTER_LEVEL;
    static boolean showReceivedData = false;
    static boolean capture = true;
    static DebugTrace trace = null;

    //----------------------------------
    // Instance data
    //----------------------------------
    boolean adjusted = false;
   JTextArea ta = new JTextArea();;
JButton btnClear = new JButton();
   JCheckBox cbCapture = new JCheckBox();
   JButton btnGetServerTime = new JButton();
   JButton btnCopy = new JButton();
   JButton btnDirect = new JButton();
   JLabel lblHost = new JLabel();
   JTextField tfHost = new JTextField();
   JLabel lblPort = new JLabel();
   JTextField tfPort = new JTextField();
   JButton btnPCMgr = new JButton();
   JSlider theSlider = new JSlider();
   JLabel lblLevel = new JLabel();

    //----------------------------------
    // DebugTrace
    //----------------------------------
    private
    DebugTrace()
    {
      super("DebugTrace window");
      try
      {
        jbInit();
      }
      catch (Exception e)
      {
        e.printStackTrace();
      }
    }

    public static boolean
    isCapturing()
    {
      return capture;
    }

    private void
    jbInit() throws Exception
    {
setLayout(null);
setVisible(false);
setSize(insets().left + insets().right + 660,insets().top + insets().bottom + 620);
setBackground(java.awt.Color.cyan);
//ta = new com.sun.java.swing.JTextArea();
ta.setEditable(false);
ta.setLayout(null);
ta.setBounds(insets().left + 12,insets().top + 25,518,576);
ta.setFont(new Font("Monospaced", Font.PLAIN, 12));
ta.setForeground(java.awt.Color.black);
ta.setBackground(java.awt.Color.white);
this.add(ta);
//btnClear = new com.sun.java.swing.JButton();
btnClear.setText("Clear");
btnClear.setActionCommand("Clear");
btnClear.setAlignmentY(0.5F);
btnClear.setToolTipText("Clears all debug messages");
btnClear.setLayout(null);
btnClear.setBounds(insets().left + 535,insets().top + 80,110,25);
btnClear.setFont(new Font("Dialog", Font.PLAIN, 12));
btnClear.setForeground(java.awt.Color.black);
btnClear.setBackground(java.awt.Color.lightGray);
add(btnClear);
//cbCapture = new com.sun.java.swing.JCheckBox();
cbCapture.setText("Capture");
cbCapture.setActionCommand("Capture");
cbCapture.setAlignmentY(0.5F);
cbCapture.setToolTipText("Toggles debug trace capturing on/off");
cbCapture.setLayout(null);
cbCapture.setBounds(insets().left + 535,insets().top + 110,110,25);
cbCapture.setFont(new Font("Dialog", Font.PLAIN, 12));
cbCapture.setForeground(java.awt.Color.black);
cbCapture.setBackground(java.awt.Color.lightGray);
add(cbCapture);
//btnGetServerTime = new com.sun.java.swing.JButton();
btnGetServerTime.setText("GetTime");
btnGetServerTime.setActionCommand("GetServerTime");
btnGetServerTime.setAlignmentY(0.5F);
btnGetServerTime.setToolTipText("Gets the time from the host specified below. Use for testing network connection speed.");
btnGetServerTime.setLayout(null);
btnGetServerTime.setBounds(insets().left + 535,insets().top + 140,110,25);
btnGetServerTime.setFont(new Font("Dialog", Font.PLAIN, 12));
btnGetServerTime.setForeground(java.awt.Color.black);
btnGetServerTime.setBackground(java.awt.Color.lightGray);
add(btnGetServerTime);
//btnCopy = new com.sun.java.swing.JButton();
btnCopy.setText("Copy");
btnCopy.setActionCommand("Copy");
btnCopy.setAlignmentY(0.5F);
btnCopy.setToolTipText("Copies trace messages to the clipboard");
btnCopy.setLayout(null);
btnCopy.setBounds(insets().left + 535,insets().top + 175,110,25);
btnCopy.setFont(new Font("Dialog", Font.PLAIN, 12));
btnCopy.setForeground(java.awt.Color.black);
btnCopy.setBackground(java.awt.Color.lightGray);
add(btnCopy);
//btnDirect = new com.sun.java.swing.JButton();
btnDirect.setText("Conn Direct");
btnDirect.setActionCommand("Direct");
btnDirect.setAlignmentY(0.5F);
btnDirect.setToolTipText("Connects directly to the UNIX backend process. Use to bypass PCMgr.");
btnDirect.setLayout(null);
btnDirect.setBounds(insets().left + 535,insets().top + 205,110,25);
btnDirect.setFont(new Font("Dialog", Font.PLAIN, 12));
btnDirect.setForeground(java.awt.Color.black);
btnDirect.setBackground(java.awt.Color.lightGray);
add(btnDirect);
//lblHost = new com.sun.java.swing.JLabel();
lblHost.setText("Host:");
lblHost.setLayout(null);
lblHost.setBounds(insets().left + 535,insets().top + 270,110,15);
lblHost.setFont(new Font("Dialog", Font.BOLD, 12));
lblHost.setForeground(java.awt.Color.black);
lblHost.setBackground(java.awt.Color.lightGray);
add(lblHost);
//tfHost = new com.sun.java.swing.JTextField();
//tfHost.setSelectionStart(7);
tfHost.setScrollOffset(43);
tfHost.setText("wilbur.kc63.att.com");
tfHost.setCaretPosition(7);
//tfHost.setSelectionEnd(7);
tfHost.setToolTipText("The UNIX host to connect to");
tfHost.setLayout(null);
tfHost.setBounds(insets().left + 535,insets().top + 290,110,25);
tfHost.setFont(new Font("SansSerif", Font.PLAIN, 12));
tfHost.setForeground(java.awt.Color.black);
tfHost.setBackground(java.awt.Color.white);
add(tfHost);
//lblPort = new com.sun.java.swing.JLabel();
lblPort.setText("Port:");
lblPort.setLayout(null);
lblPort.setBounds(insets().left + 535,insets().top + 320,110,16);
lblPort.setFont(new Font("Dialog", Font.BOLD, 12));
lblPort.setForeground(java.awt.Color.black);
lblPort.setBackground(java.awt.Color.lightGray);
add(lblPort);
//tfPort = new com.sun.java.swing.JTextField();
//tfPort.setSelectionStart(4);
tfPort.setScrollOffset(28);
tfPort.setText("1250");
tfPort.setCaretPosition(4);
//tfPort.setSelectionEnd(4);
tfPort.setToolTipText("The TCP port # of the host we're connecting to.");
tfPort.setLayout(null);
tfPort.setBounds(insets().left + 535,insets().top + 335,110,25);
tfPort.setFont(new Font("SansSerif", Font.PLAIN, 12));
tfPort.setForeground(java.awt.Color.black);
tfPort.setBackground(java.awt.Color.white);
add(tfPort);
//btnPCMgr = new com.sun.java.swing.JButton();
btnPCMgr.setText("Conn PCMgr");
btnPCMgr.setActionCommand("Direct");
btnPCMgr.setAlignmentY(0.5F);
btnPCMgr.setToolTipText("Connects using the PCMgr on the specified host/port");
btnPCMgr.setLayout(null);
btnPCMgr.setBounds(insets().left + 535,insets().top + 240,110,25);
btnPCMgr.setFont(new Font("Dialog", Font.PLAIN, 12));
btnPCMgr.setForeground(java.awt.Color.black);
btnPCMgr.setBackground(java.awt.Color.lightGray);
add(btnPCMgr);
//theSlider = new com.sun.java.swing.JSlider();
theSlider.setMinimum(500);
theSlider.setValue(500);
theSlider.setMaximum(508);
theSlider.setSnapToTicks(true);
theSlider.setToolTipText("Debug Level");
theSlider.setPaintTicks(true);
theSlider.setMajorTickSpacing(1);
theSlider.setLayout(null);
theSlider.setBounds(insets().left + 535,insets().top + 25,113,30);
theSlider.setForeground(java.awt.Color.lightGray);
theSlider.setBackground(java.awt.Color.lightGray);
add(theSlider);
//lblLevel = new com.sun.java.swing.JLabel();
lblLevel.setText("Level:");
lblLevel.setLayout(null);
lblLevel.setBounds(insets().left + 540,insets().top + 60,110,15);
lblLevel.setFont(new Font("Dialog", Font.BOLD, 12));
lblLevel.setForeground(java.awt.Color.black);
lblLevel.setBackground(java.awt.Color.lightGray);
add(lblLevel);
setTitle("DebugTrace");

//TODO: Once Visual Cafe fully support JScrollPane, let's
// add this manually. Until then, we'll have to do it ourselves
Rectangle taBounds = ta.getBounds();
remove(ta);
JScrollPane pane = new JScrollPane(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED ,ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
pane.setBounds(taBounds.x,taBounds.y,taBounds.width,taBounds.height);
pane.add(ta);
pane.getViewport().add(ta);
ta.setEditable(false);
//ta.setSize(ta.getPreferredScrollableViewportSize());
ta.setSize(taBounds.width,taBounds.height);
add(pane);
pane.getVerticalScrollBar().setUnitIncrement(1); // was 5
pane.getHorizontalScrollBar().setUnitIncrement(1);

// This is done manually also...
        theSlider.setValue(filterLevel);
        lblLevel.setText(GetFilterLevelString());

//----------------
// Action listener
//----------------
CEEActionListener theActionListener = new CEEActionListener();
btnClear.addActionListener(theActionListener);
btnGetServerTime.addActionListener(theActionListener);
btnCopy.addActionListener(theActionListener);
btnDirect.addActionListener(theActionListener);
btnPCMgr.addActionListener(theActionListener);

//----------------
// Window listener
//----------------
CEEWindowAdapter theWindowAdapter = new CEEWindowAdapter();
this.addWindowListener(theWindowAdapter);

//----------------
// Item listener
//----------------
CEEItemListener theItemListener = new CEEItemListener();

//----------------
// Change listener
//----------------
CEEChangeListener theChangeListener = new CEEChangeListener();
theSlider.addChangeListener(theChangeListener);

//cbCapture.setSelected(capture);
}

    //----------------------------------
    // Beep
    //----------------------------------
    static public void
    Beep()
    {
        java.awt.Toolkit.getDefaultToolkit().beep();
    }

    //----------------------------------
    // Create
    //----------------------------------
    static private DebugTrace
    Create()
    {
        if(trace == null)
        {
            trace = new DebugTrace();
        }
        return trace;
    }

    //----------------
    // GetFilterLevel
    //----------------
    /*
    public int
    GetFilterLevel()
    {
        return filterLevel;
    }
    */

    //----------------
    // GetFilterLevelString
    //----------------
    public String
    GetFilterLevelString()
    {
        if (filterLevel == ESConstants.ALWAYS) return "ALWAYS";
        if (filterLevel == ESConstants.NONE) return "NONE";
        if (filterLevel == ESConstants.MIN) return "MIN";
        if (filterLevel == ESConstants.MSG) return "MSG";
        if (filterLevel == ESConstants.MSGDETAIL) return "MSGDETAIL";
        if (filterLevel == ESConstants.GUI) return "GUI";
        if (filterLevel == ESConstants.GUIDETAIL) return "GUIDETAIL";
        if (filterLevel == ESConstants.COMM) return "COMM";
        if (filterLevel == ESConstants.COMMDETAIL) return "COMMDETAIL";
        if (filterLevel == ESConstants.PARANOID) return "PARANOID";
        return "UNKNOWN???";
    }

    //----------------------------------
    // GetServerTime
    //----------------------------------
    public void
    GetServerTime()
    {
        try
        {
            String host = tfHost.getText();
            int port = 13;
            Trace("Getting the time from " + host + ":" + port);
            Stopwatch sw = new Stopwatch();
            Socket s = new Socket(host,port);
            sw.Stop();
            Trace("Connection setup time" + sw);
            sw.Start();
            BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
            String line = "";
            boolean gotSomeData = false;
            while ((line = br.readLine()) != null)
            { if (gotSomeData == false)
                { gotSomeData = true;
                    sw.Stop();
                    Print("Time for server to respond = " + sw,ESConstants.ALWAYS);
                    sw.Start();
                }
                Print(line,ESConstants.ALWAYS);
            }
            br.close();
            s.close();
            sw.Stop();
            trace.Print("Finished grabbing the data" + sw,ESConstants.ALWAYS);
        }
        catch (Exception ex)
        {
            Print(ex);
        }
    }

    //----------------
    // GetTrace
    //----------------
    static public DebugTrace
    GetTrace()
    {
        return trace;
    }

    //----------------------------------
    // Hide
    //----------------------------------
    static synchronized public void
    Hide()
    {
        if(trace != null)
        { trace.setVisible(false);
        }
    }

    //----------------------------------
    // lostOwnership
    //----------------------------------
    public void
    lostOwnership(Clipboard cb, Transferable contents)
    {
    }

    //----------------------------------
    // OnCopy
    //----------------------------------
    public void
    OnCopy()
    {
        if (ta == null)
        {
            return;
        }
        String buff = ta.getText();
        if (buff.length() > 0)
        {
            Clipboard cb = getToolkit().getSystemClipboard();
            StringSelection sSelection = new StringSelection(buff);
            cb.setContents(sSelection,this);
            Beep();
        }
    }

    //----------------
    // OnDirect
    //----------------
    public void
    OnDirect()
    {
        UTDebug trace = new UTDebug("DebugTrace.onDirect()",ESConstants.COMM);

        String host = tfHost.getText();
        int port = 0;
        try
        {
            port = Integer.parseInt(tfPort.getText());
        }
        catch (NumberFormatException nfex)
        {
            trace.Print("Invalid port number (" + tfPort.getText() + ")");
            return;
        }
        trace.Print("Connecting to " + host + ":" + port);

        CommMgr cm = new CommMgr
            (ESConstants.ES_USERID,
             ESConstants.ES_PASSWORD,
             ESApplet.ES_PCMGR_HOST,
             ESApplet.ES_PCMGR_PORT,
             ESConstants.ES_PCMGR_TIMEOUT,
             ESConstants.ES_UNIX_TIMEOUT
             );
        cm.ConnectUnix(tfHost.getText(),port);

    }

    //----------------
    // OnPCMgr
    //----------------
    public void
    OnPCMgr()
    {
        UTDebug trace = new UTDebug("DebugTrace.OnPCMgr()",ESConstants.COMM);

        String host = tfHost.getText();
        int port = 0;
        try
        {
            port = Integer.parseInt(tfPort.getText());