Apache Derby, an Apache DB subproject, is a relational database implemented entirely in Java and available under the Apache License, Version 2.0.
Some key advantages include:
- Derby has a small footprint -- about 2 megabytes for the base engine and embedded JDBC driver.
- Derby is based on the Java, JDBC, and SQL standards.
- Derby provides an embedded JDBC driver that lets you embed Derby in any Java-based solution.
- Derby also supports the more familiar client/server mode with the Derby Network Client JDBC driver and Derby Network Server.
- Derby is easy to install, deploy, and use.
If you're new to Derby, check out the Quick Start page.