Well, Sun has released Java under the GPL. Interesting days ahead. I am sure there will be a lot of buzz initially, but how things play out in the future will be fun to observe. I think it is certainly a notch in Java's cap to be out under the GPL - at least from a marketing checkbox standpoint. From an enterprise customer standpoint, I'm not sure how important it will really be, or even how much of a good thing.
Java is already the world of competing technologies. There are already numerous ways and technologies available to solve any given problem, and I expect that to only proliferate in both scope (more technologies) and detail (tweaks to various "releases" of Java). The support and choice matrix will certainly grow, and I am not sure if that is a good thing. I already have customers struggling with Java environments that are a tangle of patches, OS versions, JVMs, etc. to support the numerous support and version requirements. They almost dread a new release from a support standpoint, not to mention all the tweaking and knob twisting required to get optimal performace.
I know many will say "we dont have that problem here" or "your customers must be idiots because our Java environment is as clean as can be", but I think that most fall somewhere in between. That is the beauty and the beast of .NET - simplicity in its install and for the most part support. Glitches here and there to be sure, but I would argue an order of magnititude less than Java.
Will open sourcing it make it better or worse? Only time will tell.