Oracle has announced that its JRockit Java Virtual Machine is now free for development and internal production use.

Oracle is currently working on its plans to unify the two Java Virtual Machines it owns, Hotspot and JRockit, into a single virtual machine.

Most of the work involved in this effort is engineering - taking ideas and features from JRockit and porting them over to OpenJDK - but, according to Henrik Ståhl, the JRockit product manager, Oracle has also been revieing matters from a licensing perspective. This work is now complete, and changes have been made to the Oracle (Sun) JDK and JRockit licenses which mean that JRockit is now free (gratis) for development and internal production use on general purpose computers.Commercial features, including most features currently in JRockit Mission Control, JRockit Real Time and JRockit Virtual Edition, continue to require a commercial license.

However while previously it was only possible to get a commercial license for these features as part of Oracle products (such as WebLogic Server), they can now be purchased standalone for use with any Java application. The licencsing tems also mean that just as redistribution of the JDK is permitted, this is also now also applicable to JRockit.

Henrik's blog poses and answers several questions about JRockit:

Q: Does this mean I can now use JRockit with any Java application?
A: Yes, under the same terms as you currently use the Oracle (Sun) JDK. You don't need to inform us and you don't need to pay anything.

Henrik also recomends the JRockit book (see side panel) which he comments:
is very detailed and a good read. It will also give you a good picture on what will be ported into OpenJDK as we continue to move forward.

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