This task is about adding an importer allowing to do something like:
$ guix import gradle project-url
That will run an initial gradle build of the project in a container to capture all the dynamic dependencies and turn them into origins, similar to what the cargo importer does.
The produced package will use the new gradle-build-system that will make use of these new origins, again drawing from what cargo-build-system does with the use of thecargo-inputs procedure to lookup the needed origins for a package.