Sealed interfaces and records allow you to effectively build sum types. Switch expressions with type based pattern matching really streamline certain patterns. Type inferred vars are massively welcome. Streams and lambdas are pretty old by now, but they are much more widely embraced in e.g. frameworks and std libs which is nice.

Independently none of these are game changing, but together they provide much improved ergonomics and can reduce boilerplate. Now if only we had null safe types <3.