Entity bean represents the persistent data stored in the database. It is a server-side component. In

A message driven bean (MDB) is a bean that contains business logic. But, it is invoked

Stateless Session bean is a business object that represents business logic only. It doesn't have state (data). In

Stateful Session bean is a business object that represents business logic like stateless session bean. But, it maintains

JMS (Java Message Service) is an API that provides the facility to create, send and read

Session bean encapsulates business logic only, it can be invoked by local, remote and webservice client.