More to the point, C# has integrated an excellent map-reduce framework in the guise of (P)LINQ. Java still doesn't have anything analogous to that, nor does it plan to, if the latest roadmaps are any guide.
I'm not certain that Java really needs this. Developers that wan't a more functional style should consider making a transition to Scala or Clojure.
Scala can evolve at a much faster pace than Java as well, given that the core language is tiny and most of the language constructs are implemented as libraries.
He didn't say they weren't useful, just that Java the Language doesn't need it, due to the fact other languages that have interoperability with Java on the JVM have these features already. .NET isn't as language rich as the JVM currently unless I missed some major changes.
I get that you can call across to another language that has more functional features. But that's not the same as having little bits of it right there. e.g. when you want to find the latest item in a list, instead of a loop, you do:
and carry on. It's great. You don't tend to have that fine granularity when working across languages.
I don't know if you missed F# or not, but if you want a fully functional language in the ML / Ocaml lineage on .Net, you can write some code in that and interoperate.
