FULL PRODUCT VERSION :
java version " 1.7.0_07 "
Java(TM) SE Runtime Environment (build 1.7.0_07-b11)
Java HotSpot(TM) Client VM (build 23.3-b01, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
I get 2 related NullPointerExceptions at javax.swing.text.CompositeView.replace(CompositeView.java:217) and at javax.swing.text.BoxView.paintChild(BoxView.java:161)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
It is related to the use of a custom modal internal frame in which I call the following method:

  private synchronized void startModalFrame()
  {
    try
    {
      if (SwingUtilities.isEventDispatchThread())
      {
        EventQueue theQueue = getToolkit().getSystemEventQueue();
        while (isVisible())
        {
          AWTEvent event = theQueue.getNextEvent();
          Object source = event.getSource();
          if (event instanceof ActiveEvent)
          {
            ((ActiveEvent) event).dispatch();
          }
          else if (source instanceof Component)
          {
            ((Component) source).dispatchEvent(event);
          }
          else if (source instanceof MenuComponent)
          {
            ((MenuComponent) source).dispatchEvent(event);
          }
          else System.err.println( " Unable to dispatch: " + event);
        }
      }
      else while (isVisible()) wait();
    }
    catch (Throwable ignored) {}
  }


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Repainting done properly
ACTUAL -
When NullPointerException is thrown, it will keep going on until I close the modal internal frame

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread " AWT-EventQueue-0 " java.lang.NullPointerException
at javax.swing.text.CompositeView.replace(CompositeView.java:217)
at javax.swing.text.BoxView.replace(BoxView.java:181)
at javax.swing.text.FlowView$FlowStrategy.layoutRow(FlowView.java:570)
at javax.swing.text.FlowView$FlowStrategy.layout(FlowView.java:477)
at javax.swing.text.FlowView.layout(FlowView.java:201)
at javax.swing.text.BoxView.setSize(BoxView.java:397)
at javax.swing.text.BoxView.updateChildSizes(BoxView.java:366)
at javax.swing.text.BoxView.setSpanOnAxis(BoxView.java:348)
at javax.swing.text.BoxView.layout(BoxView.java:708)
at javax.swing.text.BoxView.setSize(BoxView.java:397)
at javax.swing.plaf.basic.BasicTextUI$RootView.setSize(BasicTextUI.java:1714)
at javax.swing.plaf.basic.BasicTextUI$RootView.paint(BasicTextUI.java:1433)
at javax.swing.plaf.basic.BasicTextUI.paintSafely(BasicTextUI.java:737)
at javax.swing.plaf.basic.BasicTextUI.paint(BasicTextUI.java:881)
at javax.swing.plaf.basic.BasicTextUI.update(BasicTextUI.java:860)
at javax.swing.JComponent.paintComponent(JComponent.java:778)
at javax.swing.JComponent.paint(JComponent.java:1054)
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.paintForceDoubleBuffered(JComponent.java:1090)
at javax.swing.JViewport.blitDoubleBuffered(JViewport.java:1598)
at javax.swing.JViewport.windowBlitPaint(JViewport.java:1559)
at javax.swing.JViewport.setViewPosition(JViewport.java:1102)
at javax.swing.plaf.basic.BasicScrollPaneUI$Handler.vsbStateChanged(BasicScrollPaneUI.java:1054)
at javax.swing.plaf.basic.BasicScrollPaneUI$Handler.stateChanged(BasicScrollPaneUI.java:1043)
at javax.swing.DefaultBoundedRangeModel.fireStateChanged(DefaultBoundedRangeModel.java:364)
at javax.swing.DefaultBoundedRangeModel.setRangeProperties(DefaultBoundedRangeModel.java:302)
at javax.swing.DefaultBoundedRangeModel.setValue(DefaultBoundedRangeModel.java:168)
at javax.swing.JScrollBar.setValue(JScrollBar.java:463)



and


Exception in thread " AWT-EventQueue-0 " java.lang.NullPointerException
at javax.swing.text.BoxView.paintChild(BoxView.java:161)
at javax.swing.text.BoxView.paint(BoxView.java:433)
at javax.swing.text.BoxView.paintChild(BoxView.java:161)
at javax.swing.text.BoxView.paint(BoxView.java:433)
at javax.swing.text.ParagraphView.paint(ParagraphView.java:587)
at javax.swing.text.BoxView.paintChild(BoxView.java:161)
at javax.swing.text.BoxView.paint(BoxView.java:433)
at javax.swing.plaf.basic.BasicTextUI$RootView.paint(BasicTextUI.java:1434)
at javax.swing.plaf.basic.BasicTextUI.paintSafely(BasicTextUI.java:737)
at javax.swing.plaf.basic.BasicTextUI.paint(BasicTextUI.java:881)
at javax.swing.plaf.basic.BasicTextUI.update(BasicTextUI.java:860)
at javax.swing.JComponent.paintComponent(JComponent.java:778)
at javax.swing.JComponent.paint(JComponent.java:1054)
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:721)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:691)
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)


REPRODUCIBILITY :
This bug can be reproduced occasionally.

---------- BEGIN SOURCE ----------
public class ModalInternalFrame extends JInternalFrame
{
  private synchronized void startModalFrame()
  {
    try
    {
      if (SwingUtilities.isEventDispatchThread())
      {
        EventQueue theQueue = getToolkit().getSystemEventQueue();
        while (isVisible())
        {
          AWTEvent event = theQueue.getNextEvent();
          Object source = event.getSource();
          if (event instanceof ActiveEvent)
          {
            ((ActiveEvent) event).dispatch();
          }
          else if (source instanceof Component)
          {
            ((Component) source).dispatchEvent(event);
          }
          else if (source instanceof MenuComponent)
          {
            ((MenuComponent) source).dispatchEvent(event);
          }
          else System.err.println( " Unable to dispatch: " + event);
        }
      }
      else while (isVisible()) wait();
    }
    catch (Throwable ignored) {}
  }
}
---------- END SOURCE ----------