Java Tut – Polymorphism

Polymorphism the most common use of OOP occurs when a parent class reference is used to refer to a child class object.
Any Java object that can pass more than one IS-A test is considered to be polymorphic.In java all java objects are polymorphic since any object will pass the IS-A test for their own type and for the class object.
It is important to know that only possible way to access an object is through a reference variable.A reference varibale can only be one type.Once declared, the type of a reference variable cannot be changed.

A reference variable can be declared as a class or interface type

Let us look an example

Now the Deer class is considered to be polymorphic since this has multiple inheritance.Following are true for the above example:

Virtual Methods:
In this section,I will show you how the behavious of overriden methods in java allows you to take advantage of poly