Where is polymorphism used

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Interfaces in Java. Keywords in Java. Exception Handling in Java. Collection Framework. Multi-threading in Java. Table of Contents. One using a Salary reference s , and the other using an Employee reference e.

While invoking s. When the compiler sees e. Here, at compile time, the compiler used mailCheck in Employee to validate this statement. This behavior is referred to as virtual method invocation, and these methods are referred to as virtual methods. An overridden method is invoked at run time, no matter what data type the reference is that was used in the source code at compile time. Java - Polymorphism Advertisements. Previous Page. Next Page. In genetics , polymorphism reflects variation in the genetic coding of individuals in a population.

In the field of biochemistry , the term polymorphism is used to describe subtle structural differences in proteins that are otherwise identical. Looking at the greek roots of the term polymorphism can help to further clarify the similarities between these definitions. The word poly means "many" and the word morph means "form" , so when we talk about a polymorphism we're talking about something that appears in many different forms. This brings us to our computer science definition of polymorphism - we'll offer three different versions for maximum clarity.

Polymorphism is one of the core characteristics of any object-oriented programming language. Polymorphic code allows a program to process objects differently depending on their data type or class, with the ability to redefine methods for derived classes.

Without getting too deep into specifics of how to write polymorphic code given that it can be done differently depending on which language you use , let's review two of the most common examples used to illustrate polymorphism in computer science. Polymorphism in programming gives a program the ability to redefine methods for derived classes. Imagine that we write a piece of code where we define a base class called shape. We may want to define specific methods such as area and perimeter that can be applied to our base class - but there's a problem.

Our knowledge of geometry tells us that we cannot use the same method to compute the area and perimeter of both a circle and a rectangle. In particular, the area and perimeter of a circle depend on its radius and the area and perimeter of a rectangle depending on its width and length. To solve this problem using polymorphism coding, we could define a circle and rectangle as sub-classes or derived classes of the base class shape.

Each sub-class can have its own method for area and perimeter and each method will accept different parameters - length and width for rectangles, radius for circles.

Now our base class shape has two derived classes - rectangle and circle - each with its own methods for area and perimeter. When we call one of the methods, the provided set of parameters can be used to determine which method should be called.

If we provide a single parameter for the radius, our program can call the methods that belong to the class circle. If we provide two parameters for length and width, our program can call the methods that belong to the class rectangle. This represents a type of static polymorphism is known as method overloading. There are many different ways to implement programming polymorphism to solve problems in computer science.

Below, we briefly describe five different types of polymorphism that are commonly used in various programming languages.