打开休眠会话而不关闭它的影响

Question

I lately observed a problem in my code, I opened a hibernate session but forgot to close it. Although I fixed it but I can't seem to understand the impact of this mistake I did.

This code was in HTTP service, I need answers for two cases:

1. The container spawns a new thread when a request comes
2. It fetches from thread pool

I have read in other posts that session is bound to thread, so what I have inferred from that is if a new thread is spawned in each request and I have left a session open in one of them. It will be then destroyed when request gets completed. I dont know I am right or not.

Answer 1

It depends of what you use to control a session life cycle. If you use a "session per request pattern" with, for an example, OpenSessionInViewFilter , a session will be closed by a filter. You can use your own filter to control a session as well.

If you don't use filters or similar stuff you should always close a session. Threads that process requests know nothing about Hibernate session.

SessionFactory.openSession() always open a new session.

SessionFactory.getCurrentSession() do a check, if the current session exists — return it, if the current session doesn't exist — create a new one. A meaning of "current session" depends of a session factory parameters. In the classical case, a session is bounded to the thread (as you describe), but it can be bounded to the transaction, for an example.