Concurrent calls to session bean

What happens if I end up making concurrent calls to a session bean?

You may get an exception log starting like this:

>>>> EJB LOG >>>>
Failure in StateTransitionManager
com.inprise.ejb.StateTransitionException: Cannot invoke "afterBegin" on a bean in
state: TX_READY

It is not legal for multiple clients to use a stateful session bean. They are single user objects (or, at least, non-parallel access objects). Furthermore, the EJB specification says that a container does not have to detect invalid multiple accesses to a stateful session bean, since, in the general case, this is not possible.