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
boolean isEquivalentTo(MarkerItem item) {
			MarkerField[] fields = builder.getGenerator().getVisibleFields();
			if (cachedValues.length != fields.length)
				return false;
			for (int i = 0; i < fields.length; i++) {
				if (cachedValues[i] == fields[i].getValue(item))
					continue;
				return false;
			}
			return true;
		}
	}
	private static int instanceCount = 0;
	private static final String TAG_GENERATOR = "markerContentGenerator"; 
	private static final String TAG_HORIZONTAL_POSITION = "horizontalPosition"; 
	private static final String TAG_VERTICAL_POSITION = "verticalPosition"; 
	private static final String MARKER_FIELD = "MARKER_FIELD"; 
	/**
	 * Return the next secondary id.
	 * 
	 * @return String
	 */
	static String newSecondaryID() {
		return String.valueOf(instanceCount);
	}
	/**
	 * Open the supplied marker in an editor in page
	 * 
	 * @param marker
	 * @param page