Sure, because Java isn't a functional language. Taking a wait-and-see approach to whether the style of programming will be a fad is defensible choice when you have to support it forever. And it kind of was a fad. The only thing that really came of it in most mainstream langages is passing functions as arguments. I've yet to encounter a code-base in the wild that's actually functional.

What does functional mean to you? From my POV I see lots of features in Java coming from the functional programming world, but perhaps I have a different understanding of the term to what you do.