Wow. Pure Java edition of Berkeley DB is out. I guess pure Java version of Berkeley DB XML is coming as well. As to the performance, I haven't checked it myself but if this quote means anything, I think this is a major event for Java developers:
"With Berkeley DB Java Edition, we have a simpler setup, a 3x increase in data import speed, a 5x increase in performance and a 10x decrease in disk storage requirements."
– Eric Jain, Swiss Institute of Bioinformatics