Introduction to Polymorphism
Polymorphism is the concept with the help of which single action in different ways can be performed. It is derived from two Greek words: poly and morphs. “poly” means many, and “morphs” means forms. Henceforth, polymorphism implies many forms. Object-oriented programming can be defined as a programming language‘s ability to process objects differently depending on their class or data type. Basically, we can define it as the ability for derived classes to redefine methods.
Understanding
The two types of polymorphism are compile-time polymorphism and run time polymorphism. Compile-time polymorphism is performed by method overloading and runtime polymorphism by method overriding. Runtime polymorphism, also called Dynamic Method Dispatch, is a process wherein a call to an overridden method is resolved at runtime despite compile-time. Herein, the overridden method is called through a reference variable of a parent class. Also, Runtime polymorphism cannot be achieved by data members.
How does Polymorphism make working so easy?
It is an object-oriented programming characteristic. Using Polymorphism, a class can exhibit different functionalities even when they have a common interface. Thus, we can say that this long term explains a basic concept. The noteworthy thing about polymorphism is that all the working code in various classes does not require knowing about the class being used by it as their way of usage is the same.
It is an object-oriented programming characteristic. Using Polymorphism, a class can exhibit different functionalities even when they have a common interface. Thus, we can say that this long term explains a very basic concept. The noteworthy thing about it is that all the working code in various classes does not require to know about the class being used by it as their way of usage is the same.
Consider a real-world scenario for polymorphism. Take an example of a button. We know that we can click the button by applying some pressure, but we do not know the output of pressing the button or the reference of its use. The point here to note is that the result would not affect the way it is used either way.
So the basic goal of it is to make objects which are interchangeable depending on the needs.
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What can you do with Polymorphism?
When a child class has the same method as one declared in the parent class, we call it a method overriding.
Or in other words, if a child class provides the implementation of the method that its parent class has declared, it is called method overriding. Certain things to remember in method overriding are:
- The method must have the same name as one mentioned in the parent class
- The method must also have the same parameter as the one mentioned in the parent class.
- There must be the inheritance, that is, the IS-A relationship.
Working with polymorphism?
When a class has multiple methods that have the same name but different parameters, it is referred to as Method Overloading.
Suppose we have to perform only one operation, then having the same name as the methods would increase the readability of the program. Ways to overload the method in Java is:
- Changing the number of arguments
- Changing the data type
However, in Java, it is not possible if we change the return type of the method only.
Advantages
- It helps programmers reuse the code and the classes that are once written to be tested and implemented. (Reusability of code)
- A single variable name can store variables of multiple data types( int, float, double, long, etc.).
- Increases the readability of the program.
Why should we use polymorphism?
Apart from dynamic polymorphism and static polymorphism, some Java programming characteristics exhibit polymorphism other than the two main types.
These are – Coercion, Polymorphic Parameters, and Operator Overloading
Coercion
Let us understand coercion with a very simple example. Consider a string with the value “coercion class:”.Consider another integer with the value 1. Now, what happens when you concat a string value with an integer value? The output of this concatenation would be “coercion class: 1”. This is what is called Coercion. The implicit type conversion is done to prevent type errors. The compiler does it.
Operator Overloading
Before beginning with the operator overloading, also known as method overloading, let us go through an example. Consider a string with the value “Operator” and another string as “Overloading”. Use the plus symbol (+) with these two strings just like you add two integers. The (+) will concatenate these two strings. In the case of two integers, the sum of two integers is returned. When one symbol or operator has the ability to change their meaning depending on the way they are used, the type of polymorphism exhibited is called Operator Overloading.
Parameters
In Polymorphism, an object may appear in many forms. In Java, it refers to allowing access to an object in one of the following ways like –
1. using the reference variable of its parent class or superclass
2. using the reference variable of the class in which it exists.
Why do we need polymorphism?
The main reason why Polymorphism is needed is that this concept is widely used in implementing inheritance. It plays an important role in allowing objects to have varied internal structures in sharing the same external interface. It is stated clearly as one that is mapped for many.
Scope
Binding is connecting a method call to the method body. We have two types of binding.
Static Binding (Early Binding): When the type of object is determined at compile-time.
Dynamic Binding (Late Binding): When the type of object is determined at run-time.
Conclusion
It is thus considered as one of the very important features of Object-Oriented Programming. If you talk about a real-life example of polymorphism, it could be a person at the same time can have different characteristics; for example, a man at the same time is a son, a husband, an employee. So the same person acquires different behavior in different situations. This, in object-oriented terms, is called polymorphism, an important characteristic of object-oriented programming.
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