Enterprise Java Programming with IBM WebSphere

Chapter 27. Introduction to Message-Driven Beans

So far we have taken a fairly extensive look at entity and session beans. A common thread running through the design of all the EJBs that we have examined so far is that they all respond synchronously to local Java or RMI-IIOP calls. With the EJB 2.0 specification, a new EJB bean was introduced that allows business logic to be invoked asynchronously. MDBs are EJBs, which listen for JMS messages. In this chapter, we will introduce you to some core JMS and MDB concepts. We will begin by examining an overview of JMS, then introduce why MDBs are required, and finally examine two examples and how to execute them in the WSAD environment. Figure 27.1 shows how MDBs fit in our road map.

Figure 27.1. Where ...