Area of circle through command line argument

Area of circle through command line argument

class Circle {
  double radius;

        public Circle () {
    radius = 0;
  }
  public Circle(double r) {
  
    radius = r;
      
  }
  
  public void setLength(double r) {

    radius = r;


  }
  public double getLength () {
    return radius;  

  }
  
  public double Area() {
    return (radius * radius * 3.1459);  
  }
  public double Perimeter() {
    return (2*3.1459*radius);  
  }
}

public class CircleDemo {
  public static void main(String[] args){

                int n = args.length;
    
    if(n != 1) {
  
      System.out.println("expected one arguments");
      return;
    }

    double pr = Double.parseDouble(args[0]);
        
    Circle circ = new Circle(pr);
    double area = circ.Area();
     pr = circ.getLength();
    
    double temp = 3.1450*pr*pr;
    System.out.println(area);
    System.out.println(temp);

  

  
  }





}