@Override public Object execute(ExecutionEvent event) throws ExecutionException { final Repository repository = getRepository(true, event); // assert all resources map to the same repository if (repository == null) return null; final IResource[] resources = getSelectedResources(event); IWorkbenchPage workBenchPage = HandlerUtil.getActiveWorkbenchWindowChecked(event).getActivePage(); try { CompareUtils.compare( resources, repository, Constants.HEAD, Constants.HEAD, true, workBenchPage); } catch (IOException e) { Activator.handleError(UIText.CompareWithRefAction_errorOnSynchronize, e, true); } return null; }