Java Covariants

Question

public class CovariantTest {
    public A getObj() {
        return new A();
    }

    public static void main(String[] args) {
        CovariantTest c = new SubCov         


        

Answer 1

c is typed as CovariantTest at compile time and thus the call to c.getObj() is bound to the method CovariantTest.getObj() at compile time (and that can't be modified at runtime).

Also, x exists in both A and B (it is shadowed, not overridden). Because the method being called is CovariantTest.getObj() and that method works with A, the x being retrieved is A.x even though the actual object is of type B.