This issue is faced in Redhat Linux Advanced Server 3.0 with mustang b39. Running the attached testcase on the OS throws the following NullPointerException. This does not occur always - I could reproduce it 2 out of three times.

java.lang.NullPointerException
    at sun.awt.X11.XTrayIconPeer$TrayIconEventProxy.mouseEntered(XTrayIconPeer.java:316)
    at java.awt.Component.processMouseEvent(Component.java:5930)
    at java.awt.Component.processEvent(Component.java:5686)
    at java.awt.Component.dispatchEventImpl(Component.java:4360)
    at java.awt.Component.dispatchEvent(Component.java:4194)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:592)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:270)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:198)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:171)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:166)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:158)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:119)


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