Bug 137356 [Markers] marker grouping not working as expected via markerSupport
N20060418-0010 The Java tooling now warns when a buildpath references an execution environment for which there is no exact match in the workspace (warning support is in HEAD as of today - org.eclipse.jdt.launching and org.eclipse.jdt.debug.ui plugins). The marker created should be categorized as a buildpath problem with other JDT build path problems. To do this, I create a marker support extension as follows (in jdt.debug.ui). <extension point="org.eclipse.ui.ide.markerSupport"> <markerAttributeGrouping defaultGroupingEntry="org.eclipse.jdt.ui.category.buildpath" markerType="org.eclipse.jdt.launching.jreContainerMarker"/> </extension> My understanding is that this should group all markers of type "org.eclipse.jdt.launching.jreContainerMarker" as buildpath problems. JUI has a corresponding grouping entry: <markerGroupingEntry id="org.eclipse.jdt.ui.category.buildpath" markerGrouping="org.eclipse.jdt.ui.java_marker_category" label="%MarkerCategory.buildpath" priority="100"/> I get the following error in the log: Reference to invalid markerGroupingEntry org.eclipse.jdt.ui.category.buildpath
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerSupportRegistry.java
Object next = cache.get(key);
			if (next instanceof Collection) {
				Collection collection = (Collection) next;
				if (collection.contains(value)) {
					collection.remove(value);
					if (collection.isEmpty()) {
						keysToRemove.add(key);
					}
					break;
				}
			} else {
				if (cache.get(key).equals(value)) {
					keysToRemove.add(key);
				}
			}
		}
		Iterator keysToRemoveIterator = keysToRemove.iterator();
		while (keysToRemoveIterator.hasNext()) {
			cache.remove(keysToRemoveIterator.next());
		}
	}
	/**
	 * Get the category associated with marker. Return <code>null</code> if
	 * there are none.
	 * 
	 * @param marker
	 * @return String or <code>null</code>
	 */
	public String getCategory(IMarker marker) {
		try {