My sense is that it's because Java isn't really all that static a language. In terms of the syntax, sure. But it also relies very heavily on run-time reflection, run-time type casting, and run-time type checking. Since the introduction of generics, there are even some situations where the types are known and declared statically in the source code, but the compiler is unable to do static type verification, and so the type checking only happens dynamically at run time.
Meaning that you kind of get the worst of both worlds: High-ceremony programming, but not a whole lot of help from the compiler in return for it.
Anyway, yeah, that does mean that the debate does get more hair-splitty if we're talking Haskell vs. Racket. But, realistically, that's not usually the languages people have in mind when they're talking static vs dynamic - it's much more likely to be Java or Python. Both of which, like most languages, fall short of being the ideal examples of their respective type checking approaches.
All the stuff that happens at runtime explains the "low rewards" part, but it doesn't explain the "high investment", Java is also an extremely verbose language, doing anything is verbose and the one thing you'd want to be doing (create and use new types) is one of the most verbose parts of the language.
Records will eventually make things less bad, but a "newtype pattern" in Java takes a dozen lines or five, that's horrendous for something which should take maybe two lines. And that's before we even consider the insanity of the "one (public) class per file" mandate.
> But, realistically, that's not usually the languages people have in mind when they're talking static vs dynamic - it's much more likely to be Java or Python. Both of which, like most languages, fall short of being the ideal examples of their respective type checking approaches.
There are lots of criticisms you can leverage at Python, but it's nowhere near as bad a representative of dynamically typed language as Java is statically typed ones.
That might be one of the issues. Even when it comes to static typing java is high investment low rewards.
Things are admittedly less bad than they were 15 years ago, but it remains that java has very high overhead both syntactically and at runtime and yet is pretty limited in its static expressivity. So when you do away with java for a dynamically typed langage most of what you lost from missing static types you gain back from having so much less LOCs and ceremony and architectural astronautics to deal with.
In theory you could probably write terser java but that’s not what the community does or what the ecosystem encourage, so if you do you’re on your own and then why keep using java? There’s plenty of better langages with no community and no ecosystem out there. And they have way, way better type systems.