Your regular rosjava message project does not need this complexity!

The gradle magic in settings.gradle is responsible for kickstarting the following very useful things for a big release of message packages:

• Generating an artifact for every listed (in the package.xml) ros message package.
• Discovering & applying the underlying package version and dependency information to the artifact.

It manages the correspondence by dynamically spawning subprojects from a template build.gradle. This saves a very large amount of tedious and repetitive gradle management.

The package version and dependency information is extracted by the catkin gradle plugin that can be found in rosjava_bootstrap.