JavaRebel

Infobox_Software
name = JavaRebel



caption =
collapsible =
developer = [http://www.zeroturnaround.com ZeroTurnaround]
latest_release_version = 1.1.2
latest_release_date = release_date|2008|07|23
latest_preview_version = 1.2-M2
latest_preview_date = release_date|2008|08|07
operating_system = Cross-platform
programming_language = Java
genre = Development aids
license = Proprietary, 149$
website = http://www.zeroturnaround.com

JavaRebel is a plugin for the Java Virtual Machine that enables on-the-fly reloading of changes made to Java class files.

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.

JavaRebel 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. JavaRebel imposes a considerable performance overhead on the application and should never be used in production or performance tests. It is meant to be a development tool only.

External links

* [http://www.zeroturnaround.com/javarebel/ JavaRebel Homepage]
* [http://www.theserverside.com/news/thread.tss?thread_id=47175 JavaRebel first annoncement on TheServerSide]