Bug 80473 [rulers][preferences] allow disabling of range indicator on left of java editor
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
if (fOutlinePage == null)
				fOutlinePage= createOutlinePage();
			return fOutlinePage;
		}
		if (IEncodingSupport.class.equals(required))
			return fEncodingSupport;
		if (required == IShowInTargetList.class) {
			return new IShowInTargetList() {
				public String[] getShowInTargetIds() {
					return new String[] { JavaUI.ID_PACKAGES, IPageLayout.ID_OUTLINE, IPageLayout.ID_RES_NAV };
				}
			};
		}
		if (required == IShowInSource.class) {
			IJavaElement je= null;
			try {
				je= SelectionConverter.getElementAtOffset(this);
			} catch (JavaModelException ex) {
				je= null;
			}
			if (je != null) { 
				final ISelection selection= new StructuredSelection(je);
				return new IShowInSource() {
					public ShowInContext getShowInContext() {
						return new ShowInContext(getEditorInput(), selection);
					}
				};
			}
		}
		if (fProjectionSupport != null) {