HSQLDB
In short in HSQLDB cached table sucks in terms of performance.
HSQLDB is a high performance RDBMS written in pure Java.
I previously discussed how to extend HSQLDB relational database with simple Java functions.
HSQLDB is an unique high performing, high quality Java based relational database which can be very easily extended with simple Java static functions.
All I really want is to store a very large Hashtable with more reads than writes.