HSQL (formerly known as HypersonicSql) is an OpenSource Java database.

The project is a SourceForge project at: http://sourceforge.net/projects/hsqldb/

There are other OpenSourceJavaDatabases of which HypersonicSql is very interesting instance.

''What makes hsql "interesting"?'' -- a curious reader

HSQLDB can be used as an embedded database or as a server instance which even offers web access. HSQLDB is very fast and supports all necessary SQL commands. The database tables are stored in a simple text file (good for patching the data by hand) but can also be transformed into a cache file which improves memory usage. The performance is very good and it is very stable.

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Isn't HSQL what OpenOfficeOrg uses for its "Base" (OpenOfficeBase) product (a MicrosoftAccess clone of sorts)? Has anybody tested it for big joins? Being text-file based, join performance could be a concern. Also, I couldn't find a strait-forward ODBC driver for it.

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HypersonicSql has an In-Memory mode, which can help with writing UnitTest''''''s for things that interface with databases (see EjbUnitTest).

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CategoryDatabase