This is a partial implementation of ROS (Robotic Operating System) in Java. You're probably better off using http://wiki.ros.org/rosjava than this project.
This was originally written as a minimally functional subscriber that could listen to published messages. It has slowly expanded as I needed more functionality. It seems to work for many scenarios but is mostly undocumented and has at least one major bug (workaround: Thread.sleep(2000) after creating an action client) that make it unsuitable for all but a closely monitored labratory setting.