public void demo(File sourceCode, AnyObjectId start, AnyObjectId finish) throws IOException, GitAPIException {
        Git git = new Git(new FileRepositoryBuilder().setWorkTree(sourceCode).build());
        Iterable<RevCommit> commits = git.log().addRange(start, finish).call();
        for (RevCommit commit : commits) {
            getParents(commit);
        }
    }

    public List<RevCommit> getParents(RevCommit commit) {
        if (commit.getParents() == null || commit.getParents().length == 0) {
            return Collections.singletonList(commit);
        } else {
            List<RevCommit> parents = new ArrayList<>();
            parents.add(commit);
            for (RevCommit parent : commit.getParents()) {
                parents.addAll(getParents((parent)));
            }
            return parents;
        }
    }