Nick wrote: This is only "required" in order to bypass unapproved licenses within the source tree.
Note that this applies to ANY file added to the source tree. For example, if you write the build log to a file in the source tree (for example, with mvn package -e | tee build_log), the next build attempt will generate this license error because of this new file. But Rat will generate an error file pointing you to the culprit (normally located in [source root]/target/rat.txt). CheersAntoine