text: public Note call() throws GitAPIException {checkCallable();NoteMap map = NoteMap.newEmptyMap();RevCommit notesCommit = null;try (RevWalk walk = new RevWalk(repo)) {Ref ref = repo.exactRef(notesRef);if (ref != null) {notesCommit = walk.parseCommit(ref.getObjectId());map = NoteMap.read(walk.getObjectReader(), notesCommit);}return map.getNote(id);} catch (IOException e) {throw new JGitInternalException(e.getMessage(), e);}}