Looks like the famous, elusive html rendering timing bug in Swing
html rendering.  It pops up from time to time when using the internal
web browser as well.

Unfortunately, this is a JDK bug (as far as I know nobody's been
able to create a case where it happens consistently).  Closing as
invalid - there's nothing we can do to fix it on the in NetBeans'
code.


The code in question is:

    public void paint(Graphics g, Shape a) {
	Rectangle r;
	if (a instanceof Rectangle) {
	    r = (Rectangle) a;
	} else {
	    r = a.getBounds();  //NULL POINTER EXCEPTION HERE
	}
	painter.paint(g, r.x, r.y, r.width, r.height, this);
        super.paint(g, a);
    }

Walking the stack trace a bit, the offending rectangle is a 
"scratchpad" object allocated in the constructor of 
javax.swing.text.BoxView.  The only way I can see for it to be
null is as follows:

 - one thread constructs the BoxView instance
 - the thread scheduler switches contexts and the thread
   running the constructor is starved for a while, while
   still early in the BoxView constructor
 - another thread asks the new BoxView to paint itself before it's
   fully initialized

You might be able to achieve this once in a while
with something like SwingUtilities.invokeLater (new
BoxView(blah).paint(...)).

There is a call to 

javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.
run(SystemEventQueueUtilities.java:117)

deep in the stack trace, which suggests that could be exactly
what's happening.  I'll try to put together enough data to file
a JDK bug.

IMHO we can file a bug just from the stack trace - TableView.paint
calls View.paint (ParagraphView) with a null second Shape param, not
permitted for that method, which it got from calling
BoxView.getChildAllocation, which is documented to sometimes return
null. No idea what happened to the view that caused the child shape
allocation to be invalid, but anyway the code should be more robust
and produce a useful exception with helpful diagnostics.

Also see possibly related:

Issue #12907: AIIOBE from BoxView.updateLayoutArray, NPE from
CompositeView.replace, NPE from FlowView.FlowStrategy.adjustRow

Issue #16993: NPE from CompositeView.replace

Issue #20760: NPE from CompositeView.replace again, as well as NPE
from BoxView.calculateMajorAxisRequirements

Issue #26506: NPE from CompositeView.replace again, plus NPE from
FlowView.FlowStrategy.layoutRow, plus AIOOBE from
BoxView.updateLayoutArray, plus NPE from BoxView.layout

Issue #30188: AIIOBE from VariableHeightLayoutCache.getNode

Issue #30517: NPE from CompositeView.replace, AIOOBE from
BoxView.updateLayoutArray

Also see other bugs with ParagraphView.paint, pls. check to see if
they are the same:

Issue #9979
Issue #12907
Issue #27069
Issue #28219
Issue #29662

Found a related JDK bug 4760435 and attached link and notes.
Closing.

Hmm, I'm not convinced all of these bugs have anything to do with
#4760435, though some of them do. The Swing folks will probably ask
you to collate these stack traces better. Or they will just fix the
single exception for which a test case was given and ignore or not
notice the rest.

*** Issue 25346 has been marked as a duplicate of this issue. ***

*** Issue 33476 has been marked as a duplicate of this issue. ***

*** Issue 34601 has been marked as a duplicate of this issue. ***

*** Issue 34970 has been marked as a duplicate of this issue. ***

*** Issue 35012 has been marked as a duplicate of this issue. ***

Not our bug - closing.

*** Issue 35326 has been marked as a duplicate of this issue. ***

*** Issue 35391 has been marked as a duplicate of this issue. ***

I was having the follwing maybe related error when running my program (netbeans was not running) which contains debug code, but also libraries which don't. Therefore probably all Unknown Source references. The exception occured when selecting a cell from a table. Program had to be finished, by task manager. The code lines do not contain reference to any of my code. The program contains a lot of threading. So it is possible to be a thread issue. Note that the final routine in which the error occurs is called recursively, maybe it is possible to create code that will create this error, and/or a solution can be obtained. In my case it did not reproduce. I realize it is not a netbeans error but assume that it will reach those who are interested from here.

Thread Stopped: null null
Stack Trace: null
null
javax.swing.text.BoxView.calculateMajorAxisRequirements(Unknown Source)
javax.swing.text.BoxView.checkRequests(Unknown Source)
javax.swing.text.BoxView.getMinimumSpan(Unknown Source)
javax.swing.text.BoxView.calculateMajorAxisRequirements(Unknown Source)
javax.swing.text.BoxView.checkRequests(Unknown Source)
javax.swing.text.BoxView.setSpanOnAxis(Unknown Source)
javax.swing.text.BoxView.layout(Unknown Source)
javax.swing.text.BoxView.setSize(Unknown Source)
javax.swing.plaf.basic.BasicTextUI$RootView.setSize(Unknown Source)
javax.swing.plaf.basic.BasicTextUI$RootView.paint(Unknown Source)
javax.swing.plaf.basic.BasicTextUI.paintSafely(Unknown Source)
javax.swing.plaf.basic.BasicTextUI.paint(Unknown Source)
javax.swing.plaf.basic.BasicTextUI.update(Unknown Source)
javax.swing.JComponent.paintComponent(Unknown Source)
javax.swing.JComponent.paint(Unknown Source)
javax.swing.JComponent.paintChildren(Unknown Source)
javax.swing.JComponent.paint(Unknown Source)
javax.swing.JViewport.paint(Unknown Source)
javax.swing.JComponent.paintChildren(Unknown Source)
javax.swing.JComponent.paint(Unknown Source)
javax.swing.JComponent.paintToOffscreen(Unknown Source)
javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
javax.swing.BufferStrategyPaintManager.paint(Unknown Source)
javax.swing.RepaintManager.paint(Unknown Source)
javax.swing.JComponent._paintImmediately(Unknown Source)
javax.swing.JComponent.paintImmediately(Unknown Source)
javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknown Source)
java.awt.event.InvocationEvent.dispatch(Unknown Source)
java.awt.EventQueue.dispatchEvent(Unknown Source)
java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.run(Unknown Source)

(In reply to comment #14)
> I was having the follwing maybe related error when running my program (netbeans
> was not running)

Then file a bug for Java directly - bugs.sun.com last I checked.