Good Gear Guide
In Pictures: Six free/open source databases with c...
Apache Derby finished in the back of the pack in our review. This is an open source relational database from the Apache project. Written in Java, it will run in any Java virtual machine and has a very small footprint, which makes it an excellent choice for embedding in Java applications, such as those running on PDAs or cellphones. In terms of performance, it did not deliver the speeds of MariaDB or MySQL, but the differences were not that great.
In Pictures: Six free/open source databases with commercial-quality features