You also get compile-time error in Java switch expressions if you are not exhaustive in your cases.
But yeah, of course the design team knows about features from Scala, they are probably one of the most competent people on the Earth when it comes to PLs, and are literal CS giants.
This, along with the underscore, and even the sequence type, shows that the language designers are well aware of what Scala does, and are picking and choosing which things to bring in without risking exposing Java devs to the traditional monad salads that you see in many a Scala codebase.