Question

class A { 
    int i = 1; 
    int f() { return i; } 
} 
class B extends A { 
    int i = 2;
    int @Override f() { return -i; }
} 
public class override_test { 
    public static void main(String args[]) { 
         B b = new B(); 
         A a = (A) b;               // Cast b to an instance of class A. 
         System.out.println(a.i);   // Now refers to A.i; prints 1; 
         System.out.println(a.f()); // Still refers to B.f(); prints -2; 
    } 
}

I am wondering why a.f() still refers to B.f() while a.i refers to A.i.

thanks in advance!

Answer 1

Simple rule is when you call a method, it will be on instance type (polymorphism) in this case instance is of type B even though reference is of type A.

When you call variable, it will be on Type of the reference.

Read more about Ploymorphism