title: Java and Windows Look & feel
body: <p>I made a swing application that scans Images; and each Image represented by a leaf I a tree</p>
  
  <p>the problem that I faced is that it throws this exception </p>
  
  <pre><code>Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
      at com.sun.java.swing.plaf.windows.XPStyle$Skin.getWidth(XPStyle.java:513)
      at com.sun.java.swing.plaf.windows.XPStyle$Skin.getWidth(XPStyle.java:517)
      at com.sun.java.swing.plaf.windows.WindowsTreeUI$ExpandedIcon.getIconWidth(WindowsTreeUI.java:138)
      at javax.swing.plaf.basic.BasicTreeUI.drawCentered(BasicTreeUI.java:1580)
      at javax.swing.plaf.basic.BasicTreeUI.paintExpandControl(BasicTreeUI.java:1464)
      at javax.swing.plaf.basic.BasicTreeUI.paint(BasicTreeUI.java:1206)
      at javax.swing.plaf.ComponentUI.update(ComponentUI.java:143)
      at javax.swing.JComponent.paintComponent(JComponent.java:763)
      at javax.swing.JComponent.paint(JComponent.java:1027)
      at javax.swing.JComponent.paintToOffscreen(JComponent.java:5122)
      at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:285)
      at javax.swing.RepaintManager.paint(RepaintManager.java:1128)
      at javax.swing.JComponent._paintImmediately(JComponent.java:5070)
      at javax.swing.JComponent.paintImmediately(JComponent.java:4880)
      at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:723)
      at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:679)
      at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:659)
      at javax.swing.SystemEventQueueUtilities$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)
  </code></pre>
  
  <p>and I don't know why this appears
  Note: I am using Windows Look and feel</p>
  
  <pre><code>UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
  </code></pre>
  
  <p>and java 1.6_22
  under windows-7</p>