Bug 54900 [rulers] Java Editor does not show ruler on external Java files
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
return fProblem.getID();
			}
			/*
			 * @see IJavaAnnotation#isProblem()
			 */
			public boolean isProblem() {
				String type= getType();
				return  JavaMarkerAnnotation.WARNING_ANNOTATION_TYPE.equals(type)  ||
							JavaMarkerAnnotation.ERROR_ANNOTATION_TYPE.equals(type) ||
							SPELLING_ANNOTATION_TYPE.equals(type);
			}
			/*
			 * @see IJavaAnnotation#hasOverlay()
			 */
			public boolean hasOverlay() {
				return false;
			}
			/*
			 * @see org.eclipse.jdt.internal.ui.javaeditor.IJavaAnnotation#getOverlay()
			 */
			public IJavaAnnotation getOverlay() {
				return null;
			}
			/*
			 * @see IJavaAnnotation#addOverlaid(IJavaAnnotation)
			 */
			public void addOverlaid(IJavaAnnotation annotation) {
				if (fOverlaids == null)
					fOverlaids= new ArrayList(1);
				fOverlaids.add(annotation);