You're right - I forgot about this. I still don't think it's a valid point in this part of the discussion. Guava was/is widespread as far as I know but it's far from "everybody uses this" and while I've not worked in many Java projects, I've not seen much of this functional style. The people who wanted this badly switched to Scala. The features don't seem to be inherent, or at least not readily available to the language itself.