Rich Green, who recently returned to Sun Microsystems to head its software efforts, said that it's "not whether but how" Sun can open source Java and maintain compatibility that's delaying it from doing so.

The promise, which might take some pressure off Sun, whose proprietary-style stewardship of the technology has always been a sore spot with Java licensees, was made at the opening of JavaOne Tuesday during Sun CEO Jonathan Schwartz's keynote when Green was brought on stage.

Green said Sun was caught between a rock and a hard place - between the desire to open source Java and the fact that "compatibility matters" in a technology as ubiquitous as Java - but that it was going to be his job, now that he was back at Sun, to figure out how to do it. Sun has always been jealous of its control over Java and has voiced this logic before. Green offered no timeframe for it happening.

Of course, at 11-years-old Java is growing a bit long in the tooth and there are up-and-coming alternatives like scripting - not to mention .NET - so maybe Sun shouldn't dawdle.

Green claimed Sun needed feedback from the community and urged individual developers to join the Java Community Process (JCP). Sun is probably trying to capture the Java innovations going on in open source.

Before Java comes near to being open sourced - and Sun has been known to take its own sweet time with such things - Sun confirmed that it was making the Java Standard Edition runtime and JDK available to open source distros under a newfangled Distro License for Java (DLJ) that's supposed to make redistribution relatively unfettered.

As previously reported here, DLJ is supposed to leave communities free to define packing, installation and support for the JDK and the Blackdown Project has contributed its Debian packing code to the effort. Ubuntu, Gentoo, Debian, the Schillix and BeleniX versions of OpenSolaris and NexentaOS, the hybrid operating system with the OpenSolaris kernel and the GNU applications, are planning to redistribute the widgetry.

In the pursuit of relevance, support income and ultimately hardware revenues, Sun also open sourced or plans to open source some of its Java development tools, middleware and platform technologies claiming it delivers a completely open SOA platform.