Stateful Session Beans are the least use type of EJBs. I saw a few usages of Stateful Session Beans but most of them were improper. Stateful Session Beans are the least understood type of EJBs. What are they for? Or better: show me use cases where Stateful Session Beans are essential solution! The internet gives several answers but not always proper. We will investigate those answers.
Local EJB can be accessed by clients from the same application. But not only. The EJB specification admits that a local EJB can be accessed by any client from the same JVM. It is up to EJB Container provider if it allows such invocations. Fragment of EJB 3.1 specification: