Hi,

In J2EE environment how should I set up Session Factory for best performance? So that it is initialized only once and can be used by Session Beans. Also it is neccessary to close the SessionFactory after each method?

Thanks,
gita

Suprisingly, its hard to do in most appservers because of hierarchical class loaders. Typically, each ejb will have its own classloader. Thus, this rules out things like singletons.

I use weblogic 6x, so not sure if this solutions will work on other appservers. I actually use this approach to initialize all kinds of things I only want initialized once for the entire app. What I do is to do all this initialization in a webapp. Webapps have very clean ways of handling this. So I have an ear file containing all my ejb-jars and this war. The way weblogic works (again, can't speak about other appservers) is that the classloader for the war is the parent classloader of the classloaders for the ejbs. Thus you can even perform the initialization as a singleton in the war and have it available to the ejbs.

In JOnAS, we deploy all our beans in a single ejbjar. This way, we just have a singleton Persistence class that manages the Hibernate SessionFactory and that is shared by all beans.

This may not scale given that generating the interfaces to all beans is really a time-consuming and painful operation, and we may have to split them up. But we have already (for other reasons) verified that we can define a JOnAS startup service, which loads at startup time into the parent classloader, and which can also define the singleton Persistence object at that scope. That works for the entire application server. (Which is fine for us, since our app is the only one on the server, but might not be fine for other environments....)

Cheers,
Rob

Thanks for your reply.