Exception Handling

 class Circle
 {
    private int r;
    public void setRadius(int n) 
    {
    r=n;
    }
    public void area()
    {
        double a=3.14 * r * r;
        System.out.println("Area is "+a);
    }
 }
 class  demo
 {
    public static void main(String args[])
    {
        Circle a = new Circle();
        a.setRadius(5);
        a.area();
        System.out.println("Program End");
  }
 }

 class InvalidRadiusException extends Exception
 {
    public InvalidRadiusException(String errmsg)
    {
        super(errmsg);
    }
 }
 class Circle
 {
    private int r;
    public void setRadius(int n) 
    {
        if(n<0)
            throw new InvalidRadiusException("Invalid Radius :"+n);
        r=n;
    }
    public void area()
    {
        double a=3.14 * r * r;
        System.out.println("Area is "+a);
    }
 }
 class  demo
 {
    public static void main(String args[])
    {
        try
        {
            Circle a = new Circle();
            a.setRadius(-5);
            a.area();
        }
        catch(InvalidRadiusException er)
        {
            System.out.println("Error : "+er);
        }
        System.out.println("Program End");
    }
 }