FULL PRODUCT VERSION :
javac 1.6.0
java version 1.6.0

ADDITIONAL OS VERSION INFORMATION :
Red Hat Enterprise Linux 3 (2.4.21-37.EL)

A DESCRIPTION OF THE PROBLEM :

After uninstalling the UI on closed/disposed JDialogs, Linux clients will see the exception below. This makes the application appear broken and will generate support calls from our customers.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :

1. Compile and Run sample program on linux using JDK/JRE 1.6
2. In the sample program click button to launch a dialog (dialog A)
3. Once open, close dialog A with the uper right corner X.
4. Notice the NullPointerException (NPE) in the console console

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -

No exception should be noted.
ACTUAL -

Exception noted (see Error Messages)



ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.synth.SynthLookAndFeel$Handler.repaintIfBackgrounds
Differ(SynthLookAndFeel.java:917)
at javax.swing.plaf.synth.SynthLookAndFeel$Handler.propertyChange(SynthLookAndFeel.java:878)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
at java.awt.KeyboardFocusManager.firePropertyChange(KeyboardFocusManager.java:1387)
at java.awt.KeyboardFocusManager.setGlobalFocusOwner(KeyboardFocusManager.java:525)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:521)
        at java.awt.Component.dispatchEventImpl(Component.java:4282)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4240)
        at sun.awt.X11.XWindow$1.run(XWindow.java:352)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.lang.reflect.*;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
import javax.swing.plaf.*;


public class RepaintNPE extends JFrame
                        implements ActionListener
{
    private static class DumbDialog extends JDialog
    {
        public DumbDialog ( JFrame parent )
        {
            super ( parent, "DumbDialog", true );

            setDefaultCloseOperation ( DISPOSE_ON_CLOSE );

            JEditorPane editorPane = new JEditorPane();
            editorPane.setContentType ( "text/html" );
            editorPane.setEditable ( false );

            JScrollPane scrollPane = new JScrollPane ( editorPane );

            add( scrollPane );

            setSize( 400, 400 );

            setVisible( true );
        }

        public void dispose()
        {
            super.dispose();

            myDispose( this );
        }

        private void myDispose( Container container )
        {
            Component[] components = container.getComponents ();

            for ( Component comp : components )
            {
                // Special dispose for JComponent's remove UI
                if ( comp instanceof JComponent )
                {
                    JComponent jComp = (JComponent)comp;

                    try
                    {
                        Method method = jComp.getClass().getMethod ( "getUI" );

                        ComponentUI compUI =
                                 (ComponentUI)method.invoke ( jComp );
                        compUI.uninstallUI ( jComp );
                    }
                    catch ( Throwable t )
                    {
                        //t.printStackTrace();
                    }

                    // Recurse children
                    myDispose( jComp );
                }
            }
        }

    }

    private JButton showDialogButton = null;

    public RepaintNPE ()
    {
        setDefaultCloseOperation( EXIT_ON_CLOSE );

        showDialogButton = new JButton( "Show Dialog" );
        showDialogButton.addActionListener( this );

        add ( showDialogButton );

        setSize( 100, 100 );

        setVisible( true );

    }

    public void actionPerformed ( ActionEvent e )
    {
        if ( e.getSource() == showDialogButton )
        {
            new DumbDialog ( this );
        }
    }

    public static void main ( String args [] )
    {
        SwingUtilities.invokeLater ( new Runnable()
        {
            public void run()
            {
                try
                {
                    UIManager.setLookAndFeel(
                                  UIManager.getSystemLookAndFeelClassName() );
                }
                catch ( Throwable t )
                {
                    t.printStackTrace();
                }

                new RepaintNPE ();
            }
        } );

    }
}


---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :

None as of yet.