Bug 45062 Don't filter output folder and class files
Create a Java project with source folder src and output folder bin. The bin folder will not be shown in the Packages Explorer. Create a Java project with source folder src and output folder output/bin. The output and bin folders are shown in the Packages Explorer. Implictly filtering out bin is confusing and inconsistent. A better way to do this would be to use a name filter for bin or add "Output folder" to the list of available filters.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
if (fViewer != null)
			fViewer.removeTreeListener(fExpansionListener);
		
		if (fActionSet != null)	
			fActionSet.dispose();
		if (fFilterUpdater != null)
			ResourcesPlugin.getWorkspace().removeResourceChangeListener(fFilterUpdater);
		super.dispose();	
	}
	/**
	 * Implementation of IWorkbenchPart.createPartControl(Composite)
	 */
	public void createPartControl(Composite parent) {
		
		fViewer= createViewer(parent);
		fViewer.setUseHashlookup(true);
		if (!JavaPlugin.USE_WORKING_COPY_OWNERS) {
			fViewer.setComparer(new PackageExplorerElementComparer());
		}
		initDragAndDrop();
		
		setProviders();
		
		JavaPlugin.getDefault().getPreferenceStore().addPropertyChangeListener(this);
	
		
		MenuManager menuMgr= new MenuManager("#PopupMenu"); 
		menuMgr.setRemoveAllWhenShown(true);
		menuMgr.addMenuListener(this);
		fContextMenu= menuMgr.createContextMenu(fViewer.getTree());