As suggested in 7124552, I'm filing a separate bug about closed/java/awt/Component/6307563/bug6307563.java regression.
Here in onEDT20(), window.getBufferStrategy() is null.
Should it be not null at this moment?

java.lang.NullPointerException
at bug6307563.onEDT20(bug6307563.java:30)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at SwingTestHelper.invoke(SwingTestHelper.java:625)
at SwingTestHelper.access$800(SwingTestHelper.java:173)
at SwingTestHelper$6.run(SwingTestHelper.java:609)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:241)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
at java.awt.EventQueue.access$000(EventQueue.java:102)
at java.awt.EventQueue$3.run(EventQueue.java:662)
at java.awt.EventQueue$3.run(EventQueue.java:660)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
After a reboot of my Windows XP SP3 OS laptop, I was trying to run bugster 2.21.0.02[Production], the interface froze on me after entering the bug number to display. I "end process" the javaw process, then ran it again. Same symptom. A third time and it ran as expected. I did not cdo any clearing of caches or deleting the local Application Data/Sun/Java directories Sorry I don't have any further details.

###@###.### suggested this bug as the possible culprit if it involved BufferStragegy, and asked if I saw it again, to include the details here. The full trace disappeared off the filesystem, but at least I have the stacktrace (below).

Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Buffers have not been created
at sun.awt.windows.WComponentPeer.getBackBuffer(Unknown Source)
at java.awt.Component$FlipBufferStrategy.getBackBuffer(Unknown Source)
at java.awt.Component$FlipBufferStrategy.updateInternalBuffers(Unknown Source)
at java.awt.Component$FlipBufferStrategy.revalidate(Unknown Source)
at java.awt.Component$FlipBufferStrategy.revalidate(Unknown Source)
at java.awt.Component$FlipBufferStrategy.getDrawGraphics(Unknown Source)
at javax.swing.BufferStrategyPaintManager.prepare(Unknown Source)
at javax.swing.BufferStrategyPaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$700(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Hope this helps.