Crazy project.

Personally I find that it's an interesting indicator of the capability of the programming languages. Moving from language A to B can be extremely easy if B is as powerful or more powerful in terms of expressiveness than A. It can be an absolute horror if it is less powerful.

Being not null-safe in fact brings additional expressiveness. I guess most would argue that it's not a good type expressiveness. Nonetheless it is a type of expressiveness that can cause trouble during such a transition.

In general it feels like Java is making faster progress than Kotlin nowadays. I wonder where Kotlin would be if it weren't for Android. I hope those folks don't have to migrate back before they even finished.