Enterprise JavaBeans 3.1, 6th Edition

JMS-Based Message-Driven Beans

Message-driven beans (MDBs) are stateless, server-side, transaction-aware components for processing asynchronous messages delivered via JMS. While a message-driven bean is responsible for consuming messages, its container manages the component’s environment: transactions, security, resources, concurrency, and message acknowledgment. It’s particularly important to note that the container manages concurrency. The thread safety provided by the container gives MDBs a significant advantage over traditional JMS clients, which must be custom built to manage resources, transactions, and security in a multithreaded environment. An MDB can process hundreds of JMS messages concurrently because many underlying bean instances of the MDB can execute concurrently in the container.

A message-driven bean is a complete enterprise bean, just like a session or entity bean, but there are some important differences. While a message-driven bean has a bean class, it does not have a business or component interface. These are absent because the message-driven bean responds only to asynchronous messages and not to direct client invocations.

@MessageDriven

MDBs are identified using the @javax.ejb.MessageDriven annotation or, alternatively, are described in an EJB deployment descriptor. An MDB can be deployed alone, but it’s more frequently deployed with the other enterprise beans that it references.

@ActivationConfigProperty

We’ll see later that because MDBs can receive messages from ...