Meet the new JBoss

InfoWorld - JBoss 4.0 is remarkable in a number of ways. Not only is it an open-source, platform-independent, full Java 2 Enterprise Edition (J2EE) application server, but its installation (on Windows 2000, the operating system I tested it on) is ridiculously simple.

JBoss includes a Web server (servlet/Java Server Pages container and HTML server), Enterprise JavaBeans (EJB) 2.0 container, integrated Hypersonic 100% Java database engine, Java Messaging Services (JMS), JavaMail and Java Transaction application programming interface/Java Transaction Service transaction support. Earlier versions of JBoss used the Apache Tomcat Web server, but JBoss 4.0 is available in an Apache Tomcat version or a version that uses the embedded Jetty Web server.

JBoss 4.0 was released this year about the time of JavaOne. The JBoss Group LLC in Atlanta refers to this as a development release, appropriate as a test for development code. A production release, suitable for supporting deployed enterprise applications, will be available sometime in the fourth quarter of this year. Version 4.0 adds features such as integrated Java Data Objects (JDO), a revamped version of JMS with multicast clustering capabilities, a full implementation of J2EE 1.4 and distributed transactions.

Installing JBoss 4.0 is easy: Unzip the file and alter a couple of environment variables, and you're there. I had a small Web application Web archive (WAR) file that I had been using for Java Database Connectivity (JDBC) testing. Once JBoss was running, I dropped the WAR into the deployment directory, and the application server hot-deployed it (along with its attendant JDBC driver library). Going from download to running my Web application spanned maybe 10 minutes.

JBoss' Java Management Extensions (JMX) for application server control and configuration come into play once everything is deployed. Resource attributes and configurable parameters can be monitored and modified via Management Beans (MBeans), which are controlled in turn from the JBoss Management console. Once my servlet-based application was deployed, JBoss automatically instantiated a deployment MBean, which appeared in the JMX console's management navigation bar. From that MBean, I could deploy and undeploy the WAR application, as well as view various attributes associated with the application.

Admittedly, the JBoss management console is frugal with its graphical elements, as compared to the consoles of, say, IBM's WebSphere or BEA Systems Inc.'s WebLogic. Nevertheless, the result gets the job done. In addition, since JBoss is open-source, you can always extend the console to add whatever bells and whistles you deem necessary.

Introducing Aspects

The cornerstone of JBoss 4.0 is its aspect-oriented programming (AOP) capabilities. When properly implemented, AOP lets you