Bug 41443 overview ruler not working
smoke test for 20030812 The overview ruler in the Java editor does not work when starting with a fresh workspace as described in the smoke test scenario.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
provider= null;
					}
				}
			}
		}
		return provider;
	}
	/**
	 * Returns the annotation model associated with the document displayed in the 
	 * viewer if it is an <code>IAnnotationModelExtension</code>, or <code>null</code>.
	 * 
	 * @return the displayed document's annotation model if it is an <code>IAnnotationModelExtension</code>, or <code>null</code> 
	 * @since R3.0
	 */
	private IAnnotationModelExtension getModel() {
		ISourceViewer viewer= getSourceViewer();
		if (viewer == null)
			return null;
		IAnnotationModel m= viewer.getAnnotationModel();
		if (m instanceof IAnnotationModelExtension)
			return (IAnnotationModelExtension) m;
		else
			return null;
	}
	/**
	 * Extracts the line differ from the displayed document's annotation model. If none can be found,
	 * a new differ is created and attached to the annotation model.
	 * 
	 * @return the linediffer, or <code>null</code> if none could be found or created.
	 * @since R3.0