Question

This guide JCR Wiki proposes the use of a new session for each request. My task is to create a tree of jackrabbit files. So going by this guide to get properties/ nodes of each item, I would need to create new session and close it later? This way I would create a lot of sessions every time, which looks strange.

But if I use one session for all time for JCR I have problem with MemoryHeapException in JCR side and not right saved nodes sometimes.

Are there any norms towards an approach between using one session and creating a session every time? Or am I misreading the guide?

Answer 1

I’m more familiar with ModeShape than Jackrabbit, but in general I think it’s best practice to create a new session for each request, use that session to process the request, and then close the session.

Generally, sessions are pretty lightweight and inexpensive to create. But there are some reasons why creating separate sessions is better (or at least easier):

1. javax.jcr.Session is not thread-safe, so if you’re going to use a Session to handle multiple requests, you have to be sure that a Session is only being used in processing one request at a time. In other words, you’d some sort of pool of Sessions objects.
2. Session is stateful, so any information loaded by one session might be kept until the Session is refreshed or closed.
3. Session is for a specific user. If each incoming request might be associated with different users, you may be leaking privileges and data.

There may be other reasons I’m not thinking of, but regardless I hope this helps.