It's been a few days now, so I've had time to think about what this will mean. My interest in Sun lies primarily with MySQL, Java, VirtualBox, and Solaris. As the title indicates, I'm cautiously optimistic.
First I want to consider MySQL. On the one hand, Oracle certainly knows databases. If they choose to they can really take MySQL to the next level. On the other hand, this wouldn't be the first time Oracle has purchased a better and cheaper competitor just to kill it off **cough**Peoplesoft**cough**.
The reason I'm optimistic that they'll do the former here is that MySQL will be a lot harder to just kill off than Peoplesoft. There's a recent open source version available, and they that back. If they try, they'll find that they don't have as much power in that area as they'd hoped. They best they can do is take it closed source and then release a few compelling updates, such that much of the community follows those updates and the open source clone's can't keep up. Only then can they kill it, and even at this point I'll be surprised if there's not still a viable open source-forked clone available.
Now on to Java. Under Sun, Java was starting to fall behind. Oracle relies on Java as the natural language choice for it's database, so it has every motivation to make sure the language stays relevant. That said, it will likely continue to be the same people driving development. I am a little concerned that Oracle will decide it needs to make more money from Java, but not too concerned. After all, there are a number of good open source Java tools available now, so just like MySQL the only way Oracle can really hurt Java is if they innovate at a faster pace than the open source community can emmulate. And that's not necessarily a bad thing.
I'm a little concerned that VirtualBox will cease to be free, and become more like VMWare. There's enough room to move here that Oracle can do what it wants. It's also very possible that Oracle will have no interest in continuing the product and will just turn it over to the community or sell it to someone else.
Finally, Solaris. Solaris is pretty much irrelevant. For Oracle, it gives them a native platform for their database without dependance on anyone else... if they want to go that route. In practice, Solaris is nothing if doesn't take advantage of open source libraries and rely on open source applications. I won't be surprised if Oracle kills Solaris, but I don't think it will matter much if they do. Those who used to use it can easily migrate to linux.
