Is JGit thread safe?

[man85]

I tried to clone different repositories at the same time from different coroutines, but the process hung:

            Git.cloneRepository().setURI(p.httpUrlToRepo).setCredentialsProvider(gitCredentialsProvider)
                .setDirectory(prjPath).call()

When I added the synchronization block it was able to reach the end:

        synchronized(Git::class) {
            Git.cloneRepository().setURI(p.httpUrlToRepo).setCredentialsProvider(gitCredentialsProvider)
                .setDirectory(prjPath).call()
        }

So the question is: is JGit thread safe?