As a hypothetical, I was mainly concerned about backporting a new F21 java package as a F20 update to make it available to users still on that version, and whether that would require javadocs. Just in case, I've added a "%if 0%{fedora} < 21" condition for javadocs, and the appropriate Obsoletes line when the condition fails (>=20), but that's more to maintain in the specfile, and it'd be much simpler to just not declare any subpackaging for javadocs.