Chapter 2. Understanding message-oriented middleware and JMS


This chapter covers

  • Enterprise messaging and message-oriented middleware
  • Understanding the Java Message Service (JMS)
  • Using the JMS APIs for sending and receiving messages
  • An example of a message-driven bean

To help you better understand the ideas behind ActiveMQ, it’s important to have some background and history on enterprise messaging in general. After discussing enterprise messaging, you’ll be prepared for a brief introduction to JMS followed by some small examples of its use. The purpose of this chapter is to briefly review enterprise messaging and the JMS specification. If you’re already familiar with these topics, you can skip ahead to the next chapter.

At one time or another, every software developer needs to communicate between applications or transfer data from one system to another. Not only are there various solutions to this sort of problem, but depending on your constraints and requirements, deciding how to go about such a task can be a big decision. Business requirements often place restrictions on items that directly impact such a decision including performance, scalability, reliability, and more. There are numerous applications that we use every day that impose such requirements including ATMs, airline reservation systems, credit card systems, point-of-sale systems, and telecommunications, to name a few. Where would we be without most of these applications in our daily lives?

2.1. Introduction to enterprise messaging

2.2. What’s message-oriented middleware?

2.3. What’s the Java Message Service?

2.4. The JMS specification

2.5. Using the JMS APIs to create JMS applications

2.6. Summary