> What I wonder though is what about Java is bad? Like, is the lack of inference the key differentiator between good static type systems that help, and those that get in your way and slow you down?
Lack of type inference is part of it - Java's type system gets in your way more than better type systems due to it. But the bigger part is that Java's type system doesn't give you the tools to model things properly. One big issue is nulls - no matter what you do with types, you have the possibility of null constantly in your way. The other is the lack of sum types, without which many things that you want to model become difficult, verbose, and error-prone.
Lack of type inference is part of it - Java's type system gets in your way more than better type systems due to it. But the bigger part is that Java's type system doesn't give you the tools to model things properly. One big issue is nulls - no matter what you do with types, you have the possibility of null constantly in your way. The other is the lack of sum types, without which many things that you want to model become difficult, verbose, and error-prone.