In java, can you use the builder pattern with required and reassignable fields?

Question

This is related to the following question:

How to improve the builder pattern?

I\'m curious whether it\'s possible to implement a builder with the following

Answer 1

Why don't you want to override the setters in BuilderFinal? They would just need to downcast the super method:

public static class BuilderFinal extends BuilderC {

    @Override
    public BuilderFinal a(int v) {
        return (BuilderFinal) super.a(v);
    }

    @Override
    public BuilderFinal b(int v) {
        return (BuilderFinal) super.b(v);
    }

    public Foo build() {
        return new Foo(
                a(),
                b(),
                c());
    }
}