c3p0 is a mature, highly concurrent JDBC Connection pooling library, with support for caching and reuse of PreparedStatements. It is licensed under LGPL v.2.1 or EPL v.1.0, at your option.
c3p0 is now maintained on github.
c3p0 is available as managed dependency on Sonatype's open-source software repostory,
under [groupId: com.mchange, artifactId: c3p0] For available values of version, look here.
You can still find releases at sourceforge.
Documentation is available as part of every distribution, as well as on-line.
From the current development snapshot, here are the latest CHANGELOG and RELEASE_NOTES. For information on how to build from src, checkout README-SRC.
Please address comments and questions to the library author, although keep in mind he is an abysmal correspondent and basically an asshole. Despite that, your feedback is very much appreciated. You may also open issues on github and/or sourceforge.
Thank you for your interest in c3p0. I do hope that you find it useful!