Bug 30341 NPE attempting "Show in package explorer" [packge explorer]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
IWorkbenchPartSite site= getSite();
		site.registerContextMenu(menuMgr, fViewer);
		site.setSelectionProvider(fViewer);
		site.getPage().addPartListener(fPartListener);
		
		makeActions(); 
		
		
		restoreFilterAndSorter();
		fViewer.setInput(findInputElement());
		initDragAndDrop();
		initKeyListener();
			
		fSelectionListener= new ISelectionChangedListener() {
			public void selectionChanged(SelectionChangedEvent event) {
				handleSelectionChanged(event);
			}
		};
		fViewer.addSelectionChangedListener(fSelectionListener);
		
		fViewer.addDoubleClickListener(new IDoubleClickListener() {
			public void doubleClick(DoubleClickEvent event) {
				fActionSet.handleDoubleClick(event);
			}
		});
		
		fViewer.addOpenListener(new IOpenListener() {
			public void open(OpenEvent event) {
				fActionSet.handleOpen(event);