public  void run() 
{
            while(true) {
                // Wait on eventQueue till an event is present
                EventObject event = null;
                synchronized(eventQueue) {
                    try {
                        while (eventQueue.isEmpty())
                            eventQueue.wait();
                        event = eventQueue.remove(0);
                    } catch (InterruptedException e) {
                        // XXX Log "Event dispatch thread interrupted. Exiting"
                        return;
                    }
                }
                // Now we have event & hold no locks; deliver evt to listeners
                AbstractPreferences src=(AbstractPreferences)event.getSource();
                if (event instanceof PreferenceChangeEvent) {
                    PreferenceChangeEvent pce = (PreferenceChangeEvent)event;
                    PreferenceChangeListener[] listeners = src.prefListeners();
                    for (int i=0; i< listeners.length; i++)
                        listeners[i].preferenceChange(pce);
                } else {
                    NodeChangeEvent nce = (NodeChangeEvent)event;
                    NodeChangeListener[] listeners = src.nodeListeners();
                    if (nce instanceof NodeAddedEvent) {
                        for (int i=0; i< listeners.length; i++)
                            listeners[i].childAdded(nce);
                    } else {
                        // assert nce instanceof NodeRemovedEvent;
                        for (int i=0; i< listeners.length; i++)
                            listeners[i].childRemoved(nce);
                    }
                }
            }
}