Follow the directions listed here: http://docs.opensensorhub.org/v2/dev/dev-setup.html. After doing this:
$ cd osh-addons/dist/osh-base
$ ./gradlew build
It builds the zip file successfully, but running launch.sh from the zip fails, probably due to an out-of-date config.json. The relevant error messages appear to be these:
Caused by: java.lang.IllegalStateException: Runtime class specified in JSON is invalid: org.sensorhub.impl.service.sta.STAServiceConfig
and
Caused by: java.lang.ClassNotFoundException: org.sensorhub.impl.service.sta.STAServiceConfig