Monday, July 16, 2012


From Wikipedia, the free encyclopedia
JRebel logo
Stable release5.0.0 / June 15, 2012; 25 days ago
Written inJava
Operating systemCross-platform (JVM)
TypeDevelopment Productivity Tool
JRebel, formerly known as JavaRebel, is a plug-in for the Java Virtual Machine (JVM) that enables instant reloading of changes made to a Java class file. JRebel was developed by Jevgeni Kabanov and Toomas Römer[1] who went on to found ZeroTurnaround, a software company based inTartuEstonia. In June 2011, JRebel was recognized as "Most Innovative Java Technology" by the JAX Innovation Awards.[2] At JavaOne / Oracle Develop 2011 in San Francisco, JRebel was awarded the Duke's Choice Award for "Innovative Compiler for Java Code". [3]
Starting from version 1.4, the Java Virtual Machine includes a hot swapping feature that allows developers to update the code on-the-fly during debugging. However hot swapping was limited to updating method bodies only, and trying to add methods and fields to classes would not succeed. Since a Java compiler generates synthetic fields and methods for features like class literals and inner classes the feature was even less useful than could be expected.
JRebel is an alternative solution to updating classes which does not require a debugging session to be started. Instead it monitors the file system for changes and updates the classes in-memory. This means that only classes compiled to ".class" files will be updated and changes to classes in JAR files will be ignored. JRebel imposes a performance overhead on the application and should not be used in production or performance tests. It is meant to be a development tool only.
JRebel is Java-based and usable on any operating system that supports Java. JRebel is IDE-agnostic and designed for integration with various Java EE standards and Java application servers.[4] Although JRebel is subscription-based commercial software, it is freely available to open source software projects and developers using the Scala programming language.
JRebel supports major IDEs, including EclipseNetBeans and IntelliJ IDEA. In July, 2011, they announced a partnership with Genuitec in launching JRebel for MyEclipse.[5] In February 2012, ZeroTurnaround launched a product partnership with Vaadin, makers of the popular open source web framework.[6]




  • Immediately visible code changes without redeploying
  • Handles changes to class structures, frameworks and Java EE
  • Eliminates memory leaks during development
  • Supports all major Java application servers, IDEs and frameworks
  • Eliminates build time during development

[edit]Integration and Support

Build Tools supported[7]:
IDEs supported[7]:
Application server / containers supported[7]:
Java EE standards supported[4]:
Application and Web Frameworks supported[8]:

[edit]Licensing and Pricing

JRebel is sold as an annual subscription on a per-developer-seat basis.[9] As of September 2011, there are three for-sale versions of JRebel: JRebel Enterprise (including floating licenses and management ROI reporting features) costs 365 USD per developer per year, JRebel Base, also for teams but without the Enterprise features, costs 265 USD per developer per year, and JRebel Personal, which costs 130 USD per developer is targeted towards self-employed developers and students. Premium Support is available for teams of 10 and more developers and costs 50 USD per developer per year. JRebel is free for open source software projects and Scala developers.

[edit]See also


[edit]External links

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