Higher kinded types do make some features obsolete, but checker has MapKey checker, Lock and Index checker, and while locks may not be needed that often with everything is immutable by default mode, concurrency is hard and that alone is not always enough. While index errors are not as frequent in Haskell, due to (Head:Tail), but if you do use Array, you can’t express indexing safely without dependent types.

I’m not saying that it is better in every aspect than haskell (not too familiar with ocaml), but java is an easy and extremely popular language. And thus it has really really great tooling, and with annotations it is really extensible.

And if static analysis is not enough, there is also JML.

Also, checker taps more into intersection types, which is not really expressible in Haskell, but I’m yet again not knowledgeable enough on this latter, correct me if I’m wrong.