FULL PRODUCT VERSION :
java version "1.6.0-rc"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-rc-b70)
Java HotSpot(TM) Client VM (build 1.6.0-rc-b70, mixed mode, sharing)

FULL OS VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
Error thrown when launching application. Running fine under JSE 5.0.
I've done a little more looking into this problem. The code below is used to create a simple splash screen as the application is launching (I probably will overhaul with new splash screen functionality in mustang). In any case, if I comment out either the "setVisible(true);" lines then the runtime error does not occur (of course I don't get my splash screen either !!).

THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: Yes

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

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Launching application

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Attached seperatly

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;

class jtool_Splash extends JWindow
{
    public JProgressBar prog_bar = new JProgressBar();
    public jtool_Splash(String filename, Frame f)
    {
       super(f);
       System.out.println(System.currentTimeMillis()+"...jtool_Splash
was initiated.");
       JLabel l = new JLabel(new ImageIcon(filename));
       l.setBorder(new LineBorder(Color.black, 1,true));
       prog_bar.setBorder(new LineBorder(Color.black, 1,true));
prog_bar.setValue(0);
       prog_bar.setStringPainted(true);
       getContentPane().add(l, BorderLayout.CENTER);
       getContentPane().add(prog_bar, BorderLayout.SOUTH);
       pack();
       Dimension screenSize =
Toolkit.getDefaultToolkit().getScreenSize();
       Dimension labelSize = l.getPreferredSize();
       setLocation(screenSize.width/2 - (labelSize.width/2),
screenSize.height/2 - (labelSize.height/2));
       setVisible(true);
       System.out.println(System.currentTimeMillis()+"...jtool_Splash
was created.");
    }
}
---------- END SOURCE ----------

Release Regression From : 5.0u6
The above release value was the last known release where this
bug was known to work. Since then there has been a regression.