This is a question better suited for the Swing forum
since the exception is in Swing repainting code:
http://forums.java.net/jive/forum.jspa?forumID=74
Off the top of my head, NPEs in Swing code are very often
caused by accessing Swing components from threads other
than the Event Queue thread, although it's hard to
tell w/o reproducible test case, which I suggest you
submit when posting your question on the Swing forum.
Thanks,
Dmitri
[EMAIL PROTECTED] wrote:
I am getting random, not repeatable NPE's in at
javax.swing.BufferStrategyPaintManager.prepare. I believe they are being
caused by trying to scroll to the end of a textArea in a scrollPane. These
NPE's only seem to be happening on dual core machines on either Windows or
Linux. I believe the following code is the culprit but can't prove it. i'm
running different minor updates to Java 6.
protected final void scrollToEnd() {
if ( textArea instanceof JTextArea ) {
((JTextArea)textArea).setCaretPosition( ( (JTextComponent) textArea )
.getDocument().getLength() );
scrollPane.getVerticalScrollBar().setValue(scrollPane
.getVerticalScrollBar().getMaximum());
}
textArea.invalidate();
}
And here is a sample of the exception.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at
javax.swing.BufferStrategyPaintManager.flushAccumulatedRegion(BufferStrategyPaintManager.java:406)
at
javax.swing.BufferStrategyPaintManager.endPaint(BufferStrategyPaintManager.java:370)
at javax.swing.RepaintManager.endPaint(RepaintManager.java:1192)
at javax.swing.JComponent._paintImmediately(JComponent.java:5076)
at javax.swing.JComponent.paintImmediately(JComponent.java:4880)
at
javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:723) at
javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:679) at
javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:659)
at
javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:128)
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)
[Message sent by forum member 'diverdad' (diverdad)]
http://forums.java.net/jive/thread.jspa?messageID=270428
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