It has long been expected that Sun would open source their Java development platform. With Sun’s open sourcing of Solaris, and their overall move away from a sales based model to a support based business model, it would only make sense for them to open source Java as well.
Interestingly, Sun will go with the GPLv2 license. Traditionally, Sun has released their code under their own CDDL license, which still gives them a level of intellectual property control. The reason behind this choice of the much more viral license is to make it more compatible with the various Linux distributions, which use a lot of GPL software. Since CDDL cannot be linked against GPL code, it makes it problematic to use only CDDL.
The specific pieces of code that Sun is open sourcing under the GPLv2 are:
- The HotSpot virtual machine
- The Java Development Kit
- Java Enterprise Edition
- Java Mobile Edition
To summarize, that’s all of Java SE, Java EE, and Java ME. Or, pretty much the whole Java platform.