At the moment we only generate raw type signatures for Java UDF methods. E.g. a CQL argument type map<int, text> is just mapped to java.util.Map but could be mapped to java.util.Map<Integer, String>.
It's a probably simple but nice improvement and feels to be a LHF.
Depending on the complexity it might be doable for 3.0.x, too.
Thanks for the heads-up, DOAN DuyHai!