HSQLDB is an SQL relational database engine written in Java. It has a JDBC driver and supports a rich subset of SQL-92 (BNF tree format) plus SQL:1999 and SQL:2003 enhancements. It offers a small, fast database engine that offers both in-memory and disk-based tables. Embedded and server modes are available. Additionally, it includes tools such as a minimal web server, in-memory query and management tools (can be run as applets), and a number of demonstration examples. . Web site: http://hsqldb.org/