If you need a storage solution for your Java application, you now have
another option beside the titans MySQL and PostgreSQL: SMYLE, the
"Storage that Makes Your Life Easier".
Smyle is a versatile, highly reliable, high performance, convenient,
cross-platform database for any kind of Java application. The latest
version, Smyle 0.8, can efficiently handle tables with more than
Smyle's feature list includes: Multidimensional indexing; instant
crash recovery thanks to journalling storage model; transactions
(commit/rollback); compact store format; nestable, structured data
types; full thread safety.
Smyle is especially worth a look if you want to distribute a database
along with your application. Smyle doesn't need to be installed
seperately; it is essentially just a Java library.
Info and download at: http://smyle.sf.net