Java Abstraction

Advantages of Data Abstraction

• Implementation details of the class are protected from the unexpected user-level errors, which corrupt the state of the object.
• It helps to avoids the code duplication.
• It helps to reuse the code and provide partitioning of the code across the classes.

Abstract Class

A class which has declared as abstract is known as an abstract class. It has abstract methods and non-abstract methods. An abstract class consist of declaration as well as definition. It is a class that can't instantiated.

An abstract class is used as a base class for the deriving purpose only. An abstract class can't create an object.

 abstract class A{
	//Abstract methods
    //Non-Abstract methods
}

Abstract Method

A method which has declared as abstract and it doesn't have implementation details is known as an abstract method.

 abstract void method_name();//no method body

Example:

 abstract class Shape // abstract class
{  
	abstract void draw();  
}  
class Rectangle extends Shape
{  
	void draw()
    {
    	System.out.println("Drawing of the rectangle");
    }  
}  
class Circle extends Shape
{  
	void draw()
    {
    	System.out.println("Drawing of the circle");
    }  
}    
public class Abstractclass
{  
	public static void main(String args[])
    {  
		Shape s=new Circle();
        Shape s1=new Rectangle();
		s.draw(); 
        s1.draw(); 
	}  
}