Sun opens Java under the GPL

After years of speculation followed by years of waiting, Java has finally, truly been opened. Sun announced today that Java has made the jump to "open source," as Sun says that parts of the Java platform it owns are being licensed under the GPL open source license (version 2). The use of the GPL is surprising, because it puts any and all modifications back into the public source code, and not all software developers are eager to share their contributions. Nevertheless, in adopting the GPL, Sun is being aggressive in its move into open source. Solaris, for instance, is distributed under the far more restrictive Common Development and Distribution License (CDDL), which is mostly based on the Mozilla Public License (MPL).

The upshot is this: not only has Sun open-sourced Java, but they've adopted a license that they hope will please the "free software" folks along with the hordes of commercial software developers that have been using Java for almost a decade. Java will be distributed with what is known as a "Class path exception" which will allow Java libraries to link to non-GPLed code, making it possible to continue to use Java with closed-source commercial development projects. Sun hopes it's a win-win situation. Only time will tell.

Sun calls the move "one of the largest source code contributions under the GPL license," but the company is also quick to point out that this is big is another way, too. With 3.8 billion devices using Java, it's the single largest platform for unifying software development for devices. Sun will also continue to sell Java-based software packages despite the licensing change.

All of the source code relating to Java is expected to be opened by the end of March 2007. For now, Sun has made available the first pieces of source code for Sun's implementation of Java Platform Standard Edition (Java SE) and a buildable implementation of Java Platform Micro Edition (Java ME). More details are available at Sun's new open source Java landing.

More coverage of interest to developers can be grokked at InfoQ, which has a great run-down on the licensing ramifications.