Bug 208791 [Markers] NPE in ExtendedMarkersView
org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.NullPointerException) at org.eclipse.swt.SWT.error(SWT.java:3706) at org.eclipse.swt.SWT.error(SWT.java:3624) [... snip ...] Caused by: java.lang.NullPointerException at org.eclipse.ui.internal.provisional.views.markers.ExtendedMarkersView$10.runInUIThread(ExtendedMarkersView.java:896) at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:94) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:130) ... 52 more This brought down testResourceMappings(), but you just need to check getCategories() can return null. PW
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/ExtendedMarkersView.java
if (resource == null)
							return null;
						return (IResource) resource;
					}
				};
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.ui.ISelectionListener#selectionChanged(org.eclipse.ui.IWorkbenchPart,
			 *      org.eclipse.jface.viewers.ISelection)
			 */
			public void selectionChanged(IWorkbenchPart part,
					ISelection selection) {
				List selectedElements = new ArrayList();
				if (part instanceof IEditorPart) {
					IEditorPart editor = (IEditorPart) part;
					IFile file = ResourceUtil.getFile(editor.getEditorInput());
					if (file == null) {
						IEditorInput editorInput = editor.getEditorInput();
						if (editorInput != null) {
							Object mapping = editorInput
									.getAdapter(ResourceMapping.class);
							if (mapping != null) {
								selectedElements.add(mapping);
							}
						}
					} else {
						selectedElements.add(file);
					}