REGRESSION: Appletviewer hangs on invoking Reload button

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JDK : Mantis-rc b26, Mantis-beta
Tested OS : Windows XP pro/home, 2000 pro, ME, 98, 2003, 2003(64bit)
            Solaris9 Sparc
            Solaris9 IA
Locale : ja, C
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When I select Applet->Reoald, the applet suddenly finished, however, the process existed and the comand prompt was not returend.
In some demos Exception was thrown, in other demos no exception was thrown.

I confirmed this problem was reproducible on both of Ja and C locale(I tried the test on Solaris9 Sparc with C locale).
And I also confirmed that this problem was reproducible with Mantis-beta, but not reproducible with Hopper FCS and 1.4.1_03(I tried the test with 1.4.1_03 on Windows2000 pro.)
So this is a regression to 1.4.1 releases

To reproduce,
1)
- Launch $JAVAHOME/demo/applets/MoleculeViewer/example1.html with appletviewer
- Select Applet->Reload
Then, the applet suddenly ends and the NullPointerException is thrown and the command prompt is not returend;

java.lang.NullPointerException
         at XYZApp.newBackBuffer(XYZApp.java:296)
         at XYZApp.init(XYZApp.java:312)
         at sun.applet.AppletPanel.run(AppletPanel.java:353)
         at java.lang.Thread.run(Thread.java:534)


2)
- Launch $JAVAHOME/demo/applets/SortDemo/example1.html
- Three applets are launched.
- Select Applet->Reload in each applet.
In two applets among three Applet->Reload works fine.
But in the rest of the demo, the applet suddenly ends and IllegalArgumentException is thrown and the command prompt is not returend;

java.lang.IllegalArgumentException: null source
        at java.util.EventObject.<init>(EventObject.java:34)
        at java.awt.AWTEvent.<init>(AWTEvent.java:225)
        at java.awt.event.ComponentEvent.<init>(ComponentEvent.java:94)
        at java.awt.event.WindowEvent.<init>(WindowEvent.java:174)
        at java.awt.event.WindowEvent.<init>(WindowEvent.java:211)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:576)
        at java.awt.Component.dispatchEventImpl(Component.java:3506)
        at java.awt.Container.dispatchEventImpl(Container.java:1627)
        at java.awt.Window.dispatchEventImpl(Window.java:1606)
        at java.awt.Component.dispatchEvent(Component.java:3477)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
        at java.awt.SentEvent.dispatch(SentEvent.java:50)
        at java.awt.DefaultKeyboardFocusManager$DefaultKeyboardFocusManagerSentEvent.dispatch(DefaultKeyboardFocusManager.java:145)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

3) Other demos
When I select Applet->Reload, the applet suddenly ends, but the process exists and no command prompt is returned.


* If the priority and the severity is not appropriate, please change them.