public static RevCommit getCommonAncestor(Repository repository, RevCommit commit1,
			RevCommit commit2) {
		RevWalk walk = null;

		try {
			walk = new RevWalk(repository);
			walk.setRevFilter(RevFilter.MERGE_BASE);
			walk.markStart(commit1);
			walk.markStart(commit2);

			final RevCommit base = walk.next();

			if ((base != null) && (walk.next() == null)) {
				return base;
			}
		}
		catch (IOException e) {
			e.printStackTrace();
		}
		finally {
			if (walk != null) {
				walk.reset();
				walk.close();
				walk.dispose();
			}
		}

		return null;
	}

			walk = new RevWalk(git.getRepository());

			commit1 = walk.parseCommit(commit1);
			commit2 = walk.parseCommit(commit2);

	public static RevCommit getCommit(Repository repository, String commitId) {
		RevCommit result = null;
		RevWalk walk = null;

		try {
			final ObjectId commitObject = repository.resolve(commitId);

			if (commitObject != null) {
				walk = new RevWalk(repository);

				result = walk.parseCommit(commitObject);
			}
		}
		catch (RevisionSyntaxException | IOException e) {
			e.printStackTrace();
		}
		finally {
			if (walk != null) {
				walk.close();
				walk.dispose();
			}
		}

		return result;
	}