title: Java repaint region errors
body: <p>This is the error that i get occasionally but it halts the working of the UI</p>
  
  <p>Does anyone know how to solve it?</p>
  
  <p>This error hangs the UI generally occurs when we do repaint or update UI.</p>
  
  <pre><code>     Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
              at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(Unknown Source)
              at javax.swing.plaf.synth.SynthLookAndFeel.update(Unknown Source)
              at javax.swing.plaf.synth.SynthPanelUI.update(Unknown Source)
              at javax.swing.JComponent.paintComponent(Unknown Source)
              at javax.swing.JComponent.paint(Unknown Source)
              at javax.swing.JComponent.paintChildren(Unknown Source)
              at javax.swing.JComponent.paint(Unknown Source)
              at javax.swing.JComponent.paintChildren(Unknown Source)
              at javax.swing.JComponent.paint(Unknown Source)
              at javax.swing.JComponent.paintChildren(Unknown Source)
              at javax.swing.JComponent.paint(Unknown Source)
              at javax.swing.JLayeredPane.paint(Unknown Source)
              at javax.swing.JComponent.paintChildren(Unknown Source)
              at javax.swing.JComponent.paintToOffscreen(Unknown Source)
              at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
              at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
              at javax.swing.RepaintManager.paint(Unknown Source)
              at javax.swing.JComponent.paint(Unknown Source)
              at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
              at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
              at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
              at java.awt.Container.paint(Unknown Source)
              at java.awt.Window.paint(Unknown Source)
              at javax.swing.RepaintManager$3.run(Unknown Source)
              at javax.swing.RepaintManager$3.run(Unknown Source)
              at java.security.AccessController.doPrivileged(Native Method)
              at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
              at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
              at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
              at 
  
  javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
          at javax.swing.RepaintManager.access$1000(Unknown Source)
          at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
          at java.awt.event.InvocationEvent.dispatch(Unknown Source)
          at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
          at java.awt.EventQueue.access$200(Unknown Source)
          at java.awt.EventQueue$3.run(Unknown Source)
          at java.awt.EventQueue$3.run(Unknown Source)
          at java.security.AccessController.doPrivileged(Native Method)
          at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
          at java.awt.EventQueue.dispatchEvent(Unknown Source)
          at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
          at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
          at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
          at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
          at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
          at java.awt.EventDispatchThread.run(Unknown Source)
  </code></pre>