For MySQL, the MXJ connector makes it very easy to launch a managed MySQL instance.
I know that Oracle provides Oracle XE for quick setup, but I've only found an RPM distribution that needs to be installed. Is there a neatly packaged jar that I can just drop in the classpath and start up by calling a specific JDBC url, a la HSQLDB or MXJ?
I'm interested in having developers use this locally for running tests, as well as on our continuous integration server.