Why I cannot access Child Object method with Parent Type

Question

object a2 is of type A but references an object of class C. So, a2 should be able to access m3(). But, why is it not happening? If m3() method had been defined in class A, t

Answer 1

You see the subclass C as an instance of A because an A does not have the function m3 that a C has.

  A a2 = new C();

So here, you can access only the methods in C that are inherited from A. You basically see it as an A. If you wanted to call the methods in C, you would have to cast it to C, so you'd have to do something like this:

 if(a2 instanceof C)
 {
     C castedA2 = (C)a2;
     castedA2.m3();
 }