No, I don't think Java will have multiple, vendor-specific variants. Once the source is opened, the primary control Sun will have is over the trademark.

With Unix, various licensing deals meant lots of companies could sell something called "Unix", no matter how incompatible it was. As long as Sun cares, all they need do is deny the right to use the Java™ name to any implementation that doesn't meet their compatibility criteria.

As the article points out, Sun can't stop open source Java from happening, so the question becomes which they would prefer: incomplete, slow, open-source VMs developed by volunteers or a complete, thoroughly-tested open-source VM (HotSpot). Opening the HotSpot source actually reduces forking, because developers and distributors are more likely to just use HotSpot than to try to develop their own.

For the record I did not say "just a few months". I said "in months, not years" indicating the timescale is not a distant one. But it's not as near as IDG is implying either.

IMHO the key to successful open source projects is good leadership. Linux and Apache have them. If open source Java has good leadership and a good process for managing change, there's no reason to assume it will fork. Based on these other projects, I think the fear of forking is a red herring.

Should we care about Java Variants? Since the dawn of hard drives, time-stressed people have tended to choose vendor locked technologies. More "resourced" people do not. Given few can see where their code will wind up, it is simply a "pay now", or "pay latter" choice. IMO, most of us should be more worried about the rate of framework deprecation, than language syntax variations. Caveat developer: For every COBOL, there should ever be a WATBOL. Open source or no, natural "selection" is the price we pay for progress... .NET, anyone?

Maybe Sun is just looking in the mirror too much. Kaffe seems nice, nice website. They have competition already. Competition is a good thing I think. They'll have to form a Java community base like the Linux Standard Base though if there are a lot of forks then the fork has to comply. Do they have something like this with their GPL: hardware and software?
I have heard they don't want it to be like Linux. Well Linux is Linux no matter how many forks there are. Java is Java.

Also there could be languages that might appear similar to Java but want to retain separate.