StreamCruncher 1.08 Beta is ready, with support for the pure Java, PointBase Database. PointBase is probably the most widely used embedded Java Database. HSQL might beat it in terms of sheer number of Desktops it is deployed on, as part of OpenOffice.

Even though PointBase does not support an In-Memory mode, the Database Page Size, Cache Flush Time and other settings can be modified to reduce Latency.