java.lang.NullPointerException
        at org.netbeans.modules.editor.NbToolTip$Request.run(NbToolTip.java:452)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:576)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1013)
Caused: org.openide.util.RequestProcessor$Item: task failed: java.lang.NullPointerException
        at org.openide.util.RequestProcessor$Item.fillInStackTrace(RequestProcessor.java:853)
        at java.lang.Throwable.<init>(Throwable.java:181)
        at java.lang.Exception.<init>(Exception.java:29)
        at org.openide.util.RequestProcessor$Item.<init>(RequestProcessor.java:819)
        at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:629)
        at org.openide.util.RequestProcessor.post(RequestProcessor.java:295)
        at org.openide.util.RequestProcessor.post(RequestProcessor.java:266)
        at org.netbeans.modules.editor.NbToolTip.buildTip(NbToolTip.java:292)
        at org.netbeans.modules.editor.NbToolTip.buildToolTip(NbToolTip.java:109)
        at org.netbeans.modules.editor.NbEditorKit$NbBuildToolTipAction.actionPerformed(NbEditorKit.java:615)
        at org.netbeans.editor.BaseAction.actionPerformed(BaseAction.java:325)
        at org.openide.awt.AlwaysEnabledAction.actionPerformed(AlwaysEnabledAction.java:115)
        at org.netbeans.editor.ext.ToolTipSupport.updateToolTip(ToolTipSupport.java:460)
        at org.netbeans.editor.ext.ToolTipSupport.setToolTipVisible(ToolTipSupport.java:487)
        at org.netbeans.editor.ext.ToolTipSupport.actionPerformed(ToolTipSupport.java:761)
        at org.netbeans.editor.WeakTimerListener.actionPerformed(WeakTimerListener.java:85)
        at javax.swing.Timer.fireActionPerformed(Timer.java:271)
        at javax.swing.Timer$DoPostEvent.run(Timer.java:201)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)