required fields don't do anything in Java

[shashachu]

They add @NonNull annotations, but otherwise, there's no consequence. If I have a model with a required field, I'd expect that MyModel.builder().build() would throw an exception, but as it is, it allows you to build a model with null required fields.

[rahul-malik]

I think this seems related to the issue around adding validation methods #185

[shashachu]

Haha I'm disagreeing with my past self.