Conditional stm - switch & if-then-elseif

public class Order {
  boolean isFilled;
  double billAmount;
  String shipping;

  public Order(boolean filled, double cost, String shippingMethod) {
        if (cost > 24.00) {
      System.out.println("High value item!");
    }
    isFilled = filled;
    billAmount = cost;
    shipping = shippingMethod;
  }

  public void ship() {
    if (isFilled) {
      System.out.println("Shipping");
      System.out.println("Shipping cost: " + calculateShipping());
    } else {
      System.out.println("Order not ready");
    }
  }

  //using switch statement
  public double calculateShipping() {
    double shippingCost;

    switch (shipping){
      case "Regular":
        shippingCost = 0;
        break;
      case "Express":
        shippingCost = 1.75;
        break;
      default:
        shippingCost = 0.50;
    }

    return shippingCost; //remember to return the variable
    }

    /*
    //using if-then-elseif statement
    public double calculateShipping() {
        // declare conditional statement here
    if (shipping == "Regular"){
      return 0;
    }
    else if (shipping == "Express"){
      return 1.75;
    }
    else return 0.50;
    }

    */

  public static void main(String[] args) {
    // do not alter the main method!
    Order book = new Order(true, 9.99, "Express");
    Order chemistrySet = new Order(false, 72.50, "Regular");

    book.ship();
    chemistrySet.ship();
  }
}