[REQ][JAVA] Add @Nullable/@Nonnull annotations to POJO attributes and setters

[nvervelle]

I'm using java generator for webclient, and the generated POJO classes only contain @Nullable/@Nonnull annotations for the getters, but not for the attributes themselves or the setters.

When using tools like NullAway, it causes some issues because you cannot easily use the fluent setters when setting a nullable attribute, because the setter is not annotated with @Nullable.

I'd like to add the annotations to the attributes and the setters, so that it's easier to enable tools like NullAway on code using the generated clients.

I will submit a PR for this feature request.

[nvervelle]

PR submitted : #19617

[c99SRS]

Hi @nvervelle pls assign this to me. Want to work on this

[nvervelle]

@c99SRS : the PR is submitted, what is the work you were thinking of ?