java.lang.NullPointerException
        at org.netbeans.modules.editor.NbEditorDocument.createEditor(NbEditorDocument.java:170)
        at org.openide.text.CloneableEditor$DoInitialize.initCustomEditor(CloneableEditor.java:377)
        at org.openide.text.CloneableEditor$DoInitialize.initVisual(CloneableEditor.java:479)
        at org.openide.text.CloneableEditor.getEditorPane(CloneableEditor.java:945)
        at org.netbeans.modules.java.hints.infrastructure.HintAction.getCurrentFile(HintAction.java:112)
        at org.netbeans.modules.java.hints.infrastructure.HintAction.updateEnabled(HintAction.java:69)
        at org.netbeans.modules.java.hints.infrastructure.HintAction.propertyChange(HintAction.java:145)
        at org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:186)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
        at org.netbeans.core.windows.RegistryImpl.doFirePropertyChange(RegistryImpl.java:315)
        at org.netbeans.core.windows.RegistryImpl.topComponentClosed(RegistryImpl.java:196)
        at org.netbeans.core.windows.WindowManagerImpl.notifyRegistryTopComponentClosed(WindowManagerImpl.java:1033)
        at org.netbeans.core.windows.WindowManagerImpl.notifyTopComponentClosed(WindowManagerImpl.java:1005)
        at org.netbeans.core.windows.Central.removeModeTopComponent(Central.java:972)
        at org.netbeans.core.windows.ModeImpl.removeTopComponent(ModeImpl.java:410)
        at org.netbeans.core.windows.ModeImpl.close(ModeImpl.java:243)
        at org.netbeans.core.windows.WindowManagerImpl.topComponentClose(WindowManagerImpl.java:1157)
        at org.openide.windows.TopComponent.close(TopComponent.java:449)
        at org.openide.windows.TopComponent.close(TopComponent.java:435)
        at org.netbeans.core.windows.actions.ActionUtils.closeWindow(ActionUtils.java:350)
        at org.netbeans.core.windows.actions.CloseWindowAction$1.run(CloseWindowAction.java:100)
        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)