A database written in Java? You gotta be kidding. They released Eclipse and plugins. Eclipse is an IDE made with Java. Maybe they released some atents for OSS use that related to DB2 that caused the confusion.
IBM did make a java db OS last year. The Database that IBM released is Cloudscape. It's a pretty cool product actually. It is written in java, and is embedded, if I'm using that term correctly. We used it for a school project a while back. It's just a small .jar file that you include and configure with your java app.
http://www-306.ibm.com/software/data/cloudscape/
Hmmm.... I doubt it. They released a database written in Java, but DB2 is IBM's answer to a database for the big iron.
DB2 is still IBM's flagship DB. Lots of DB2 engine development happens in Lenexa.
Matt