A quick little note to mention the official release of Java 6. Okay, Dan, but why do you care?, you might ask. Good question, oh person-who-does-not-read-headlines.
The reason I care is that Sun chose to bundle Apache Derby in this release -- take a peek in the /db/ subdirectory of the Java SDK. Bundling Derby is going to mean a huge boost to the visibility and usage of the little Java database that could. It will be the de facto default database for Java developers; and if they haven't already used it, I suspect they're going to be pleasantly surprised at Derby's robustness and ability to perform. I was chatting with a few of the DSpace developers a week or so ago, and mentioned my hope (in all my spare time) to port the DSpace institutional repository to Derby as a possible default database. Right now, you see, the default database for DSpace is PostgreSQL, and unfortunately correctly configuring PostgreSQL seems to be the biggest barrier new users encounter while deploying DSpace. Switch to an embedded Derby database, and those headaches go away.
On the other hand, it seems that at least one of the DSpace developers have done a bit of experimenting with Derby in the past, as he claimed its performance suffered after 500,000 rows of data or so. Well, even if that is an insurmountable limit, that's a pretty good start for most institutional repositories -- and I suspect that the Derby developers would be highly motivated to show that Derby can, in fact, scale beyond that limit.
So, if you're a Java developer or dabbler, get on out there and give Derby + Java 6 a try. You're going to have a lot of company. Oh yeah, and if you need a good book on Derby...