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Java Toolmaker Battles Redeployment with a JRebel Yell

Java toolmaker ZeroTurnaround has broadened its "attack campaign against redeploys, the natural enemy of Java developers," says its says CEO David Booth, with the release of JRebel 4.0, the latest version of a JVM plug-in designed to allow developers to make on-the-fly code changes in Java class files.

ZeroTurnaround claims that Java developers spend an average of 10.5 minutes of every coding hour redeploying their apps to see changes. The company bases that claim on its own recent survey of 1,000+ Java EE developers on turnaround time, tools, and application containers in the Java ecosystem. The company's raizon d'etre is to reduce that time, Booth said.

"When Java developers want to see the effects of new code (or make changes to existing code), they have to redeploy their entire application -- even to see the smallest changes," Booth said in a statement. "We'd like to enable Java developers to start up their container when they start working, and know that's the last time they'll have to do it all day. With JRebel 4.0, we're 95% of the way there."

The JRebel plug-in is designed to integrate with the JVM and app servers on the class loader level, so it doesn't create new class loaders, but extends existing ones.

Version one of the plugin was released more than three years ago. This latest version supports reloading changes to Enterprise JavaBeans 3.x, anonymous class reloading, the Instrumentation API and HotSwap, and Full Seam 2.x. This version is also expands support to 35 frameworks. The company emphasizes that JRebel uses the Instrumentation API to instrument the application server class loaders and other basic classes, "…but the API does not play part in the actual reloading process…."

JRebel supports Java 1.4 and Java 5+. It also supports a number of application servers, including, among others: WebLogic, WebSphere, Tomcat, JBoss, GlassFish, Google's App Engine, Apple's Web Objects, Jetty, and NetWeaver.

The company has also integrated JRebel with the Eclipse IDE. JRebel for Eclipse is available from the Eclipse Marketplace.

The company sells the JRebel plug-in on an annual subscription basis, but it's offering a 30-day eval download.

Posted by John K. Waters on June 9, 2011