Need help with Polymorphism please help !!

Question

let's say we have two classes (A and B) while B inherits from A and they both have the same methode called AlphabetOrder() that returns the order of the letters A or B in the alphabet so in this case 1 or 2 , so when we do :

A obj=new B();
System.out.println(obj.AlphabetOrder());

Why it goes always for the B methode despite the obj is of type A?

Answer 1

B class overridden A method.
Inheritance means B inherited some methods in A. And if not overridden it will use A methods. However you should not be able to do the following:
B obj = new A ();
Since B might have methods A does not have.

Polymorphism defines a base class (which can be virtual. That means that all descendant Classes must implement the virtual methods).
However you can have a base class container var or var [] that contains descendant objects but uses the correct method that they share.