Bug 270952 [CommonNavigator] Eclipse RCP raises nullPointerException in makeSmallString for Project Explorer
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceLabelProvider.java
private void findUpdateLabel(NavigatorContentExtension foundExtension, ReusableViewerLabel label, TreePath elementPath) {
		
		ILabelProvider labelProvider = foundExtension.getLabelProvider();
		if (labelProvider instanceof ITreePathLabelProvider) {
			ITreePathLabelProvider tplp = (ITreePathLabelProvider) labelProvider;
			tplp.updateLabel(label, elementPath);
		} else {
			label.setImage(labelProvider.getImage(elementPath.getLastSegment()));
			label.setText(labelProvider.getText(elementPath.getLastSegment()));
		}		
		 
		if(shouldContinue(label, foundExtension)) {
			findUpdateLabel(contentService.getExtension(foundExtension.getDescriptor().getOverriddenDescriptor()), label, elementPath);
		}   
	}
 
	private boolean shouldContinue(ReusableViewerLabel label, NavigatorContentExtension foundExtension) {
		if(foundExtension.getDescriptor().getOverriddenDescriptor() != null) {			
			return !(label.isValid() && label.hasChanged()); 
		}
		return false;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ILabelProviderListener#labelProviderChanged(org.eclipse.jface.viewers.LabelProviderChangedEvent)
	 */
	public void labelProviderChanged(LabelProviderChangedEvent event) { 
		fireLabelProviderChanged(event);		
	}
}