C-JDBC

Gives your applications a transparent (no code modification) access to a cluster of databases even if your database engines are not cluster-aware.

C-JDBC is an open source (LGPL) database cluster middleware that allows any Java application (standalone application, servlet or EJB container, ...) to transparently access a cluster of databases through JDBC(tm). The database is distributed and replicated among several nodes and C-JDBC balances the queries among these nodes. C-JDBC handles node failures and provides support for checkpointing and hot recovery.