Sun's 'Mustang': Open, But Not Open SourceSun's 'Mustang': Open, But Not Open Source

Sun Microsystems is releasing early source code snapshots of its next desktop Java release, aiming to get more outside programmers involved in the development process.

The company last month released J2SE 5.0, also known as "Tiger," and recently started work on the next version of J2SE. Although the project, code-named "Mustang," is still in its earliest stages, Sun has posted the code on its Java.net Web site for developers to download, test, and evaluate.

Sun also posted pre-release developer snapshots of Tiger, but the code was not made available until last June, after the company's developers completed a substantial amount of work. This time, according to a Sun executive's Weblog entry, the company wants developers to participate in the Mustang effort almost from the very beginning.

"We posted each weekly Tiger build, in binary form, from the Beta 2 release right up to the Release Candidate," wrote Mark Reinhold, Sun chief engineer for the J2SE platform. About 10,000 people downloaded the code during that time, he said, and several dozen bug reports were filed, including several fixed in time for the release candidate.

Reinhold noted the Mustang snapshots will provide complete J2SE source bundles, something Sun has never before done while a release is under active development. "This should make it easier for interested developers to contribute to the release as it evolves," he stated.

"In past releases the only ways to do that were to be lucky and know someone at Sun, or be lucky and have your suggestion survive the labyrinthine gauntlet of the bug-submission process," Reinhold added.

The Mustang source bundles will be available to developers under Sun's Java Research License (JRL), which Reinhold described as "more flexible" and easier to understand than the Sun Community Source Licensing model used with the Tiger pre-release code.

As Reinhold noted, however, the JRL is not an open-source license, and developers who submit code to the Mustang project are required to surrender ownership rights, including copyright, to Sun.

Sun has come under increasing pressure from the open-source community to release Java as an open-source technology. Sun representatives have stated in the past that Java will eventually become an open-source project, but they have not discussed details or specific dates for such a move. The company has released an experimental Java user interface, Looking Glass, under an open-source license, and it plans to release an open-source version of Solaris 10.

Sun currently expects Mustang to be ready for general release in the first half of 2006.