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 (monitor.isCanceled())
					return Status.CANCEL_STATUS;
				
				
				if (builder.getGenerator().isShowingHierarchy()
						&& categoriesToExpand.isEmpty()) {
					MarkerCategory[] categories = builder.getCategories();
					if (categories.length == 1)
						categoriesToExpand.add(categories[0].getName());
				}
				getViewer().refresh(true);
				updateTitle();
				if (preservedSelection.size() > 0) {
					Collection newSelection = new ArrayList();
					MarkerItem[] markerEntries = builder.getMarkerEntries();
					for (int i = 0; i < markerEntries.length; i++) {
						Iterator preserved = preservedSelection.iterator();
						while (preserved.hasNext()) {
							MarkerSelectionEntry next = (MarkerSelectionEntry) preserved
									.next();
							if (next.isEquivalentTo(markerEntries[i])) {
								newSelection.add(markerEntries[i]);
								continue;
							}
						}
					}
					getViewer().setSelection(
							new StructuredSelection(newSelection.toArray()),
							true);
					preservedSelection.clear();