The following is excerpted from ActiveMQ in Action by Bruce Snyder, Dejan Bosanac, and Rob Davies with permission from Manning Publications Co.
Chapter 1. Introduction to Apache ActiveMQYou can download Chapter 1: An Introduction to Messaging and Apache ActiveMQ or find out more about the book by taking a look at the listing for ActiveMQ in Action on the Manning website. If you decide to buy the book online, be sure to enter the coupon code "activemq40" and get the SearchSOA.com readers' discount.
Enterprise messaging software has been in existence since the late 1980s. Not only is messaging a style of communication between applications, it is also a style of integration. Therefore, messaging fulfills the need for both notification as well as interoperation amongst applications. However, it's only within the last 10 years that open source solutions have emerged. Apache ActiveMQ is one such solution, providing the ability for applications to communicate in an asynchronous, loosely-coupled manner. This chapter will introduce you to ActiveMQ.
ActiveMQ is an open source, JMS 1.1 compliant, message-oriented middleware (MOM) from the Apache Software Foundation that provides high-availability, performance, scalability, reliability and security for enterprise messaging. ActiveMQ is licensed using the Apache License, one of the most liberal and business friendly OSI-approved licenses available. Because of the Apache License, anyone can use or modify ActiveMQ without any repercussions for the redistribution of changes. This is a critical point for many businesses who use ActiveMQ in a strategic manner. As described later in Chapter 2, the job of a MOM is to mediate events and messages amongst distributed applications, guaranteeing that they reach their intended recipients. So it's vital that a MOM must be highly available, performant and scalable.
The goal of ActiveMQ is to provide standards based, message-oriented application integration across as many languages and platforms as possible. ActiveMQ implements the JMS spec and offers dozens of additional features and value on top of this spec. These additional features will be introduced and discussed in detail throughout this book.
Your first steps with ActiveMQ are important to your success in using it for your own work. To the novice user, ActiveMQ may appear to be daunting and yet to the seasoned hacker, it might be easier to understand. This chapter will walk you through the task of becoming familiar with ActiveMQ in a simple manner. You will gain not only a high level understanding of the ActiveMQ feature set, but you will also be taken through a discussion of why and where to use ActiveMQ in your application development. Then you will be be prepared enough to install and begin using ActiveMQ.
This was first published in October 2010