A copy of the code from http://code.google.com/p/onejar-maven-plugin/. Please see this site for usage information. The only difference here is that this plugin is available in Maven Central.
The only difference when using this version is that there is no separate repository required and that the groupId
has to be set to com.jolira.
A very simple example for a pom.xml using this plugin can be found at https://raw.github.com/jolira/device-detector/master/pom.xml.