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Abstract in java

Introduction 

    A class define using abstract keyword is called Abstract class. Abstraction is a process of hiding the implementation and provide the functionality to user in other word it hide the details and show only functionality. The genreal example is SMS function in mobile. We dont know actualy how it work but we know how to use it. There are two way to archive abstraction.

  1. Abstract class
  2. Interface


1. Abstract Class:

    A class define using abstract keyword is called Abstract class. It have abstract and non-abstract both the method. It need to be extend and methods to be implemented. It cannot be instantiated.

Main Points to remember:

👉 An abstract class must be declared with an abstract keyword.

👉 It can have abstract and non-abstract methods.

👉 It cannot be instantiated.

👉 It can have constructors and static methods also.

👉 It can have final methods which will force the subclass not to change the body of the method.

    Abstract Methods:

A method which is declared as abstract and does not have implementation is known as an abstract method.

Syntax of abstract method:

abstract void printStatus();    //no method body and abstract  

Example od abstract Class:

abstract class Bike{  

  abstract void run();  

}  

class Honda4 extends Bike{  

void run(){System.out.println("running safely");}  

public static void main(String args[]){  

 Bike obj = new Honda4();  

 obj.run();  

}  

}  

OUTPUT:

running safely

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