Aside from the often cited nullability issue, here is an (incomplete) list of important things that Kotlin still does better than Java:

- First class, fully functional closures. - Non-abstract classes and methods are final by default. - Named parameters. - Easy to write iterators via sequence { ... } - First class support for unsigned types.

Also the ability to just put a function somewhere in the “bare” part of a namespace was something I didn’t realize I missed as much as I did.