Differences between Message-Driven Beans and Stateless Session EJBs

Chapter 8 Creating J2EE Applications for BEA WebLogic

Differences between Message-Driven Beans and Stateless Session EJBs

In several ways, the dynamic creation and allocation of message-driven bean instances mimics the behavior of stateless session EJB instances. However, message-driven beans are different from stateless session EJBs (and other types of EJBs) in several significant ways:

Message-driven beans process multiple JMS messages asynchronously, rather than processing a serialized sequence of method calls.
Message-driven beans have no home or remote interface, and therefore cannot be directly accessed by internal or external clients. Clients interact with message-driven beans only indirectly, by sending a message to a JMS Queue or Topic.

Note that only the WebLogic Server container directly interacts with a message-driven bean by creating bean instances and passing JMS messages to those instances as necessary.
WebLogic Server maintains the entire life cycle of a message-driven bean; instances cannot be created or removed as a result of client requests or other API calls.