Hi Janda,
I don't understand how did you get NPE with provided stacktrace?
JComponent#paintComponent cannot get g = null, because of in the
previous JComponent#paintChildren method we have the following code:
Graphics cg = sg.create(cr.x, cr.y, cr.width,
cr.height);
cg.setColor(comp.getForeground()); // here will
be NPE when cg is null
I'm also not sure that it's valid situation to pass in the
JComponent#paintComponent method null as a Graphics. Could you please
provide a small test?
Regards, Pavel
protected void paintComponent(Graphics g) {
if (ui != null) {
Graphics scratchGraphics = (g == null) ? null : g.create();
try {
ui.update(scratchGraphics, this);
}
finally {
scratchGraphics.dispose(); // here is NPE
when input 'g' is null
}
}
}
uname -a
Linux linux-tp9a 2.6.25.20-0.4-default #1 SMP 2009-06-01 09:57:12 +0200 x86_64
x86_64 x86_64 GNU/Linux
java version "1.6.0_25"
Java(TM) SE Runtime Environment (build 1.6.0_25-b06)
Java HotSpot(TM) Server VM (build 20.0-b11, mixed mode)
Stack trace
AWT-EventQueue-0@2851, priority=6, in group 'main', status: 'RUNNING'
at javax.swing.JComponent.paintComponent(JComponent.java:755)
at javax.swing.JComponent.paint(JComponent.java:1,029)
at javax.swing.JComponent.paintChildren(JComponent.java:862)
at javax.swing.JComponent.paint(JComponent.java:1,038)
at javax.swing.JComponent.paintChildren(JComponent.java:862)
at javax.swing.JComponent.paint(JComponent.java:1,038)
at javax.swing.JComponent.paintChildren(JComponent.java:862)
at javax.swing.JComponent.paint(JComponent.java:1,038)
at javax.swing.JComponent.paintToOffscreen(JComponent.java:5,124)
at
javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:278)
at javax.swing.RepaintManager.paint(RepaintManager.java:1,224)
at javax.swing.JComponent._paintImmediately(JComponent.java:5,072)
at javax.swing.JComponent.paintImmediately(JComponent.java:4,882)
at
javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
at
javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
at
javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
at
javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
at java.awt.EventQueue.access$000(EventQueue.java:84)
at java.awt.EventQueue$1.run(EventQueue.java:602)
at java.awt.EventQueue$1.run(EventQueue.java:600)
at
java.security.AccessController.doPrivileged(AccessController.java:-1)
at
java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
at
java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at
java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
