Abstraction

Abstraction is a concept which shows only important(essential) feature and hide background details. In other way, abstraction shows only those things to user which are important and hides the background details. for eg :- example of abstraction is tv remote, we press its button and see that channel get change, but we did not its internal processing.

we achieve abstraction in java by :-

• Abstract class
• Interface

ABSTRACT CLASS

we use abstract keyword for defining abstract class. That means a class which contain abstract keyword is a abstract class.

syntax

    abstract class A{} 

example :-

abstract class Print{  
abstract void draw();  
}  
        //In real scenario, implementation is provided by others i.e. unknown by end user  
class A extends Print{  
void draw(){System.out.println("A class implementing method of Print class");}  
}  

class B extends Print{  
void draw(){System.out.println("B class implementing method of Print class");}  
}  

             //In real scenario, method is called by programmer or user  
class Abstraction{  
public static void main(String args[]){  
Print s=new B();//In real scenario, object is provided through method e.g. getShape() method  
s.draw();  
}  
}  

OUTPUT

B class implementing method of Print class