Try single level inheritance with Super Class as Final

Define a Super
Class as final and try to show single level inheritance. 

final
class A

 {

  protected double l,b;

  A(double x,double y)

   {

    l=x;

    b=y;

   }

  double CalArea()

    {

     System.out.println("Class A");

     return (l*b);

    }

 }

class
B extends A

 {

  B(double x,double y)

   {

    super(x,y);

   }

  double CalArea()

    {

     System.out.println("Class B");

     return (l*b);

    }

 }

class
Sk15

 {

  public static void main(String args[])

   {

    B obj=new B(5.5,6.5);

    double a= obj.CalArea();

    System.out.println("Area= "+a);

    }

 }

Compile:

D:\>javac
Sk15.java

Error:

D:\SK>javac
Sk15.java

Sk15.java:17:
cannot inherit from final A

class
B extends A

                ^

1
error