persistent object modification by different threads safe?

[ppphoenixxx]

Hi,

according to EJB3-Specs a single EntityManager object isn't thread-safe, so the same EntityManager shouldn't be used by different threads: but what about obtaining a set of persistent objects, applying some changes on them in a *different* thread, where no EntityManager methods are called or used?

Well it works, right out of the box: no EntityManager.clear or merge calls needed in the "original" thread - but I have no idea if this is safe, supposed to work or should be avoided at all costs: I only know that I spare myself a little work by not going the usual way to get me another session bean and obtain an entity manager there.

To give you some details about the application I am writing: Its a standard EJB3 one, with some persistent objects and a built in callback-server which listens in a different thread on a specific network port for connections and should do some persistent operations upon a callback-connection from a client.

Thanks for any input!

[ppphoenixxx]

Well it works, right out of the box: no EntityManager.clear or merge calls needed in the "original" thread - but I have no idea if this is safe, supposed to work or should be avoided at all costs

Okay, avoid! First I thought it works, but now it doesn't: so if it worked at all (was quite tired when I tried it), its absolutely unreliable.

For the record: I moved to a different approach:

1st) cache my persistent entities
2nd) detach from them
3rd) work on the cached state, update them as I need to (even from different threads)
4th) update the cached state periodically with a Timer

Thats accurate enough for me and I can react on events like callbacks immediately.