Open Source Java

Sun recently announced the distribution of Java in open source. To be more specific, it means that J2ME would be open sourced soon, J2SE in six months or so (both J2ME and J2SE Sun implementations released under GPL2 with classpath exception), and Glassfish (J2EE implementation by Sun) changed from CDDL to GPL (GPL2 w/ CP exception).

This is good news for the Java and open source communities. Distribution of J2SE and J2ME under an open source licence will undoubtedly foster the adoption of these technologies. It makes Java clearly 'compatible' with Linux - and will please all open source proponents (and users) that were a little concerned to use Java open source projects while still relying on a close source VM. Now it will be possible to have a full open source stack (e.g. Linux + J2SE + open source middleware + bespoke or OTS applications).

The choice of GPL is meaningfull, and a clear signal toward Linux - at a time when Microsoft and Novell signed a deal around virtualization technology. Java (SE and EE) can also be considered as a virtualization platform (remember 'build once run everywhere'?) from hardware independance all the way up to the Grid.

Sun has been playing with legal frameworks to ensure compatibility of open source projects to the JSRs (e.g. J2EE certification of JOnAS, JBoss, Geronimo) and now has enough experience to make sure that open source implementations of J2[SME]E remain interoperable (and compliant w/ the specs) even in case of fork. The idea is simple: you do what you want with the source code, but to call the binary 'Java' you have to have it certified. The keystone of this scheme is Sun's control over the 'Java' trademark(s).

Yet this may not be the end of the story. What will be the answer from OS communities such as Apache (with Harmony), who've been historically (and geographically) very close to Sun, and who advocate for so-called 'business friendly' open source licenses (APL*) ? What will be Sun's position wrt GPL v3?