Sorry to have been so prompt. What I meant was "if you want more than that, I would recommand Scala".
Scala is close to Java because it compiles to JVM and you can use Java libraries in scala (so that's not a big deal to switch to it). You can nearly code in scala like in Java with some syntax improvment and in a functional way.
I agree with him - what Guava brings (functional programming, better safety in types) is something that is better done at language level like in Scala.
Either you like Java and you don't need Guava, or you want functional programming and other goodness and for that Scala is a better language.
I really find this kind of Snark disappointing on HN, and one of the many examples of a decline in the quality of comments that PG has talked about.