derby database -apache

Apache Derby, an Apache
DB subproject, is an open source relational database implemented entirely in Java and available 

http://db.apache.org/derby/

oozie is based on it.

http://oozie.apache.org/docs/4.0.0/DG_QuickStart.html

These instructions install and run Oozie using an embedded Tomcat server and an embedded Derby database.
http://www.agile-engineering.net/2011/11/test-doubles-with-mockito.html