The latest version of InfinityDB, v1.0.19, contains
new data types and new example code.

InfinityDB is a fast, high-reliability, data-compressing embeddable
Java database engine. Use global transactionality to ensure your
application-level consistency, while relying on InfinityDB's
journaling system to guarantee database internal structural integrity
at all times, with instant recovery after power failure. Minimize disk
footprint using prefix and suffix compressed variable-size data items
stored using UTF-8 over ZLib in variable-size blocks. Quickly master
the simple API, and use flexible, runtime-extensible data structures
that superset the relational model. Smooth Threading and watch
performance soar.

For a free trial download, see:
http://www.boilerbay.com/infinitydb/