Mondrian is an OLAP (online analytical processing) engine written in Java. It reads from JDBC data sources, aggregates data in a memory cache, and implements the MDX language and the olap4j and XML/A APIs.
OpenDigger is a java based compiler for the xETL language. xETL is a language specifically projected to read, manipulate and write data in any format and database. With OpenDigger/XETL you can build powerful Extraction-Transformation-Loading (ETL) progs!