My understanding is that the vast majority of Java development is done in shops where conformance to coding and pattern "standards" is valued as a way of allegedly making the code base easier to read and understand (I am not agreeing with this, just stating what I believe they believe).

If my understanding is correct, which shop is going to allow people to start using these new techniques, when they already have a code base full of workarounds? Unless someone is going to sit down and refactor their humun-gi-normous code base, they will in effect be creating a second dialect of Java in their shop if they start using traits and closures instead of whatever they were already doing with Java's existing feature set.

I just can't see this having any more than a token impact. Now Java users can say, "Sure we have closures. We don't use them here, but they exist and if we wanted to, we could use them. But we don't need them, so it's no big deal."