RosJava
Rosjava provides both a client library for ros communications in java as well as growing list of core tools (e.g. tf, geometry) and drivers (e.g. hokuyo).
Official source code for rosjava projects can be found on github in the rosjava organisation.
Documentation
The documentation on the wiki here provides a general overview of the rosjava ecosystem and install/build instructions. For tutorials and coding level API documentation, refer to the github generated documentation. Links below.
Overview : what to expect and what tools are used for rosjava development.
Official Packages : list of all official and semi-official packages in the rosjava-android ecosystem.
Anatomy : the anatomy of a typical rosjava package.
Environment Variables : some environment variables that can influence the build of rosjava stacks.
Messages : messages are handled slightly differently in rosjava.
RosJava Core Api Docs : detailed coding level documentation and tutorial information.
FAQ : frequently asked questions.