Drill uses two license header checkers:
Apache RAT Plugin is used because it is the standard license header checker for Apache projects.
License Maven Plugin performs stricter license checks and supports disallowing license headers wrapped in /** and **/. This
allows us to inforce requiring all license headers to be wrapped only in /* and */.
The license checks are disabled locally by default and are enabled on Travis. If you'd like to perform license checks locally you can do the following:
mvn license:check -Dlicense.skip=false
If the license checks fail and you can't figure out what's wrong with your headers, you can auto-format your license headers with the following command:
mvn license:format -Dlicense.skip=false
This command will also add license headers to files without them.