Slight confusion regarding overriding where variables are concerned

Question

I\'m preparing for the SCJP (recently rebranded as OCPJP by Oracle) and one particular question that I got wrong on a mock exam has confused me, the answer description doesn

Answer 1

The technical term for what is happening here is "hiding". Variables names in Java are resolved by the reference type, not the object they are referencing.

• A object has a A.x variable.
• B object has both A.x and B.x variables.

However instance methods with the same signature are "overridden" not "hidden", and you cannot access the version of a method that is overridden from the outside.

Note that hiding also applies to static methods with the same signature.

Your mock question in a simplified form (without overriding):

class A {
    int x = 5;
}

class B extends A {
    int x = 6;
}

public class CovariantTest {

    public static void main(String[] args) {

        A a = new B();
        B b = new B();
        System.out.println(a.x); // prints 5
        System.out.println(b.x); // prints 6

    }
}