Why polymorphism

The word polymorphism is used in various contexts and describes situations in which something occurs in several different forms. In computer science, it describes the concept that objects of different types can be accessed through the same interface. Each type can provide its own, independent implementation of this interface. It is one of the core concepts of object-oriented programming OOP. Due to this, all objects in Java are polymorphic because they pass at least two instanceof checks.

Java, like many other object-oriented programming languages, allows you to implement multiple methods within the same class that use the same name but a different set of parameters. That is called method overloading and represents a static form of polymorphism. In most cases, each of these overloaded methods provides a different but very similar functionality. Due to the different sets of parameters, each method has a different signature. That allows the compiler to identify which method has to be called and to bind it to the method call.

This approach is called static binding or static polymorphism. I use the same CoffeeMachine project as I used in the previous posts of this series. The BasicCoffeeMachine class implements two methods with the name brewCoffee. The first one accepts one parameter of type CoffeeSelection. The other method accepts two parameters, a CoffeeSelection , and an int.

Now when you call one of these methods, the provided set of parameters identifies the method which has to be called. In the following code snippet, I call the method only with a CoffeeSelection object. To simply put, polymorphism in java allows us to perform the same action in many different ways. Any Java object that can pass more than one IS-A test is considered to be polymorphic and in java, all the java objects are polymorphic as it has passed the IS-A test for their own type and for the class Object.

There are two types of polymorphism in java: compile-time polymorphism and runtime polymorphism. This article also talks about two types of polymorphism in Java: compile-time polymorphism and runtime polymorphism, java polymorphism examples, method overloading, method overriding, why to use polymorphism in java and many more.

Polymorphism is a feature of the object-oriented programming language, Java, which allows a single task to be performed in different ways.

In the technical world, polymorphism in java allows one to do multiple implementations by defining one interface. Participate in regularly organized career accelerated programs and placement drives offered by Great Learning and get hired by the top leading companies across different industries. What is Polymorphism? What is Polymorphism in Java? What is Method Overriding in Java? What is Runtime Polymorphism in Java? Runtime polymorphism with multilevel inheritance.

What is Compile-Time Polymorphism in Java? What is polymorphism in programming? What is Polymorphism variables? Why use Polymorphism in Java?

Advantages of Polymorphism in Java Characteristics of Polymorphism. The derivation of the word Polymorphism is from two different Greek words- poly and morphs. So polymorphism means innumerable forms. Polymorphism is one of the most significant features of Object-Oriented Programming. Polymorphism in Java can be defined as a task that can perform a single action in different ways. Languages that do not support polymorphism cannot be referred to as Object-Oriented Languages.

But instead, they are known as Object Bases Languages. Ada is an example of one such Language. Since Java supports polymorphism, it is an Object-Oriented Language. Polymorphism occurs when there is inheritance, i. Inheritance is a powerful feature in Java.

Inheritance lets one class acquire the properties and attributes of another class. Polymorphism in java allows us to use these inherited properties to perform different tasks.

Thus, allowing us to achieve the same action in many different ways. An individual can have different relationships with different people. A woman can be a mother, a daughter, a sister, a friend, all at the same time, i. But if you use polymorphism you are going to remove the if conditions by extending the generic FlyMachine class and overriding the getFlyingSpeedInMph as below.

Polymorphism gives you benefits only if you need Polymorphism. It's used when an entity of your conceptual project can be seen as the specialization of another entity. The main idea is "specialization". A great example stands in the so called Taxonomy,for example applied to living beings. Dogs and Humans are both Mammals. This means that, the class Mammals group all the entities that have some properties and behaviors in common.

So both have a isThereFuel because when you drive a car you expect to know if there's fuel enough for driving it. Another great concept is "expectation". It's always a great idea to draw an ER entity relationship diagram of the domain of your software before starting it. That's because your are forced to picture which kind of entities are gonna be created and, if you're able enough, you can save lot of code finding common behaviors between entities.

But saving code isn't the only benefit of a good project. You might be interested in finding out the so called "software engineering" that it's a collection of techniques and concepts that allows you to write "clean code" there's also a great book called "Clean code" that's widely suggested by pro-grammes. The good reason for why Polymorphism is need in java is because the concept is extensively used in implementing inheritance.

It plays an important role in allowing objects having different internal structures to share the same external interface. Suppose there are different kinds of machines like car, scooter, washing machine, electric motor, etc.

But the logic to start and stop a machine is different for each machine. Here, every machine will have different implementations to start and stop. So, to provide different implementations we need polymorphism. Here we can have a base class machine with start and stop as its methods and each machine type can extend this functionality and Override these methods. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Why to use Polymorphism? Ask Question. Asked 9 years, 5 months ago.

Active 2 years, 10 months ago. Viewed 84k times. Improve this question. Ben Davis October 15, Why do we need polymorphism? What is the function of polymorphism? Are humans polymorphic? What are the advantages and disadvantages of polymorphism?

Which can show polymorphism? Which of the following is incorrect for polymorphism? What is difference between compile time and run time polymorphism? Why it is called compile time polymorphism? Why it is called runtime polymorphism?

Why method overriding is called dynamic polymorphism? What is difference between static and dynamic polymorphism? What is overloading and overriding? Can final method be overloaded? What is the advantage of method overloading? What is polymorphism overloading and overriding?

Is polymorphism and overriding same? What can be used in place of overloading? What is difference between polymorphism and overloading?