super keyword in Java

Hello friends how are you, today in this blog i will teach you what is super keyword, in how many ways super keyword can be used, how super keyword works and many programs using super keyword in a very simple way. 

Let's start

1.super is a keyword that refers to the object of current base class .
2.It can be used to replace derived class variable with base class level variable.
3.It is also used to call parent/base class method/function.
4.It is also used to call parent/base class overloaded constructor.

1. super keyword with variable

By using super keyword we can replace derived class variable with base class variable. For better understanding see the below example.

 
//Base class  
class Parameter
  {
    int height=10,width=20;
  }
//derived class
class Rectangle extends Parameter
{
    int height=5,width=6;
    public void area() 
    {
     int ar;
     ar=height*width;
     System.out.println("Area without super="+ar);
     //here derived class variable is replaced with base class variable
     ar=super.height*super.width;
     System.out.println("Area with super="+ar);
    }
  }
class Easy
{
 public static void main(String[] args)
 {
  //Creating instance(object) of  class
  Rectangle obj=new Rectangle();
  obj.area();
 }
}
/*
### Output ###
Area without super=30
Area with super=200
*/

2. super keyword with function

By using super keywrod we can also call base class function from derived class. For better understanding see the below example.

//Base class  
class Square
  {
    void area(int side)
    {
    int ar=side*side;
     System.out.println("Area of square="+ar);
    }
  }
//derived class
class Rectangle extends Square
{
    int height=5,width=6;
    public void area() 
    {
     int ar;
     ar=height*width;
     System.out.println("Area of Rectangle="+ar);
     //calling base class function using super keyword
     super.area(10);
    }
  }
class Easy
{
 public static void main(String[] args)
 {
  //Creating instance(object) of  class
  Rectangle obj=new Rectangle();
  obj.area();
 }
}
/*
### Output ###
Area of Rectangle=30
Area of square=100
*/

3. super keyword with constructor

By using super keywrod we can also call constructor of base class function from derived class. For better understanding see the below example.

//Base class  
class Square
  {
    //paramaterised constructor of base class
    Square(int side)
    {
    int ar=side*side;
     System.out.println("Area of square="+ar);
    }
  }
//derived class
class Rectangle extends Square
{
    int height=5,width=6;
  //default constructor of derived class
    Rectangle() 
    {
    //calling base class constructor
     super(12);
     int ar;
     ar=height*width;
     System.out.println("Area of Rectangle="+ar);
    }
  }
class Easy
{
 public static void main(String[] args)
 {
  //Creating instance(object) of  class
  Rectangle obj=new Rectangle();
 }
}
/*
### Output ###
Area of square=144
Area of Rectangle=30
*/

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