Java Code Generator

[Jamalam360]

Description
Codegen for Java.

It'd have to make a top level class that holds static classes for the actual schemas (so Schemas.EmailRequestOut for example), unless the codegen emitted multiple files.

Additional context
I am happy to work on this if it will be considered.

[stepchowfun]

This would be great to have, and it would be welcome as a contribution. Is there a way we can do it that gives the benefits of non-nullable types and exhaustive pattern matching (e.g., with the visitor pattern)?