Sun Microsystems plans to publish the first open source Java code by October this year, the company has revealed.

Laurie Tolson, vice president of developer programmes and products at Sun, said at a company event that the first components include Java C and the Hotspot VM. The remainder of the code will be open sourced by the end of 2007.

Sun first announced that it would release the Java source code under an open source licence at JavaOne in May. 

The company is still considering the licence under which it will release the technology, and has launched a special website, Open Sourcing the JDK, soliciting feedback from developers. 

"Our primary focus is to be compatible, putting programmes in place that people can rely on for compatible implementations of Java," said Tolson.

Sun has also expanded its open source Java initiative with the Java ME technology that allows mobile phones to run Java code. It has not been made clear whether the mobile version of Java would be included in the open source initiative.

There is, however, a clear trend towards the use of open source software on mobile phones, according to Alan Brenner, vice president of mobile and embedded devices at Sun.

Brenner pointed at the consortium set up in June by Motorola, NEC, Panasonic, Samsung, NTT DoCoMo and Vodafone which seeks to create a standard version of mobile Linux.

"So far we have clearly seen that going in an OS direction for Java ME is the right and logical choice at this point. We really do want to lead and establish that direction in the market," said Brenner.

He added that "most" of Java ME will be released under an open source licence by the end of 2006.

• A video interview on open source Java with Rich Green, Sun's senior vice president for software, is available on the Silicon Valley Sleuth blog.