Polymorphism is an object-oriented programming concept which is used for a variable, function or object to take on multiple forms. Polymorphism is born from word ploy and morphism, Poly means many and Morphism forms means that we can perform single or same action at different- enjoinment. Polymorphism is the ability of an object to take on many forms. The most common use of Polymorphism in 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 Polymorphism. In Java all Java objects are in Polymorphism form since any object will pass the IS-A test for their own type and for the class Object.