Yes. The feature has been proposed for Java too: "defender methods".

Originally I resisted them on the grounds of not being necessary, but they're used all over now. Being able to supply a default implementation is extremely useful.

Quick correction: Java 8 does have defender methods.

default method implementations makes traits behave like mixins, it's very useful (and it is a form of code reuse).

Totally agreed. I was wrong to resist them :)

Thanks to all for explanations! :) And now I think Traits are traits, but can be used as interfaces too :)

Yes: http://rustbyexample.com/trait.html

They can also contain associated constants.