<Swing Dev> May AbstractButton.doClick() be called by non-edt threads?

[Clemens Eisserer]

Hi,

I recently got a really strange NPE when running Java2Demo, and by
looking at the code it seems this NPE can only be caused by threading
violations.
(Component.maxSizeSet set to true, while Component.maxSize not visible)

I had a look at Java2Demo's source, where I found code like this
(ClipAnim.DemoControls.run()):

@Override
        public void run() {
            ((AbstractButton) toolbar.getComponentAtIndex(2)).doClick();
        }

According to CustomControls.start(), this overriden run-method is
executed on a fresh thread, so outside of the EDT.
May AbstractButton.doClick() be called from outside the EDT?

Furthermore, is there any reason CustomControls.stop() is
synchronized, while start() isn't?

Thanks, Clemens


Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at java.awt.Dimension.<init>(Dimension.java:111)
	at java.awt.Component.getMaximumSize(Component.java:2751)
	at java.awt.Container.getMaximumSize(Container.java:1887)
	at javax.swing.JComponent.getMaximumSize(JComponent.java:1698)
	at javax.swing.BoxLayout.checkRequests(BoxLayout.java:484)
	at javax.swing.BoxLayout.preferredLayoutSize(BoxLayout.java:300)
	at javax.swing.JToolBar$DefaultToolBarLayout.preferredLayoutSize(JToolBar.java:771)
	at java.awt.Container.preferredSize(Container.java:1788)
	at java.awt.Container.getPreferredSize(Container.java:1773)
	at javax.swing.JComponent.getPreferredSize(JComponent.java:1662)
	at java.awt.FlowLayout.layoutContainer(FlowLayout.java:609)
	at java.awt.Container.layout(Container.java:1503)
	at java.awt.Container.doLayout(Container.java:1492)
	at java.awt.Container.validateTree(Container.java:1688)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validate(Container.java:1623)
	at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:653)
	at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1620)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:705)
	at java.awt.EventQueue.access$000(EventQueue.java:101)
	at java.awt.EventQueue$3.run(EventQueue.java:666)
	at java.awt.EventQueue$3.run(EventQueue.java:664)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:675)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)


Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at javax.swing.BoxLayout.preferredLayoutSize(BoxLayout.java:301)
	at javax.swing.JToolBar$DefaultToolBarLayout.preferredLayoutSize(JToolBar.java:771)
	at java.awt.Container.preferredSize(Container.java:1788)
	at java.awt.Container.getPreferredSize(Container.java:1773)
	at javax.swing.JComponent.getPreferredSize(JComponent.java:1662)
	at java.awt.FlowLayout.layoutContainer(FlowLayout.java:609)
	at java.awt.Container.layout(Container.java:1503)
	at java.awt.Container.doLayout(Container.java:1492)
	at java.awt.Container.validateTree(Container.java:1688)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validateTree(Container.java:1697)
	at java.awt.Container.validate(Container.java:1623)
	at javax.swing.plaf.basic.BasicTabbedPaneUI.ensureCurrentLayout(BasicTabbedPaneUI.java:1446)
	at javax.swing.plaf.basic.BasicTabbedPaneUI.paint(BasicTabbedPaneUI.java:787)
	at javax.swing.plaf.metal.MetalTabbedPaneUI.paint(MetalTabbedPaneUI.java:843)
	at javax.swing.plaf.metal.MetalTabbedPaneUI.update(MetalTabbedPaneUI.java:724)
	at javax.swing.JComponent.paintComponent(JComponent.java:778)
	at javax.swing.JComponent.paint(JComponent.java:1054)
	at javax.swing.JComponent.paintChildren(JComponent.java:887)
	at javax.swing.JComponent.paint(JComponent.java:1063)
	at javax.swing.JComponent.paintToOffscreen(JComponent.java:5221)
	at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:295)
	at javax.swing.RepaintManager.paint(RepaintManager.java:1206)
	at javax.swing.JComponent._paintImmediately(JComponent.java:5169)
	at javax.swing.JComponent.paintImmediately(JComponent.java:4980)
	at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:770)
	at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:728)
	at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:677)
	at javax.swing.RepaintManager.access$700(RepaintManager.java:59)
	at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1621)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:705)
	at java.awt.EventQueue.access$000(EventQueue.java:101)
	at java.awt.EventQueue$3.run(EventQueue.java:666)
	at java.awt.EventQueue$3.run(EventQueue.java:664)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:675)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)