Bug 30341 NPE attempting "Show in package explorer" [packge explorer]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
boolean showCUChildren= PreferenceConstants.getPreferenceStore().getBoolean(PreferenceConstants.SHOW_CU_CHILDREN);
			((StandardJavaElementContentProvider)fViewer.getContentProvider()).setProvideMembers(showCUChildren);
			
			refreshViewer= true;
		} else if (PreferenceConstants.APPEARANCE_MEMBER_SORT_ORDER.equals(event.getProperty())) {
			refreshViewer= true;
		}
		if (refreshViewer)
			fViewer.refresh();
	}
	
	/* (non-Javadoc)
	 * @see IViewPartInputProvider#getViewPartInput()
	 */
	public Object getViewPartInput() {
		if (fViewer != null) {
			return fViewer.getInput();
		}
		return null;
	}
	public void collapseAll() {
		fViewer.getControl().setRedraw(false);		
		fViewer.collapseToLevel(getViewPartInput(), TreeViewer.ALL_LEVELS);
		fViewer.getControl().setRedraw(true);
	}
	
	public PackageExplorerPart() { 
	}
}