Java: ButtonGroup will not display

Question

Cannot make my ButtonGroup display for the first two checkboxes. Attempted to add them, which seems successful, however the group will not show. Do you see what I did incorrectly?

  import javax.swing.*;
  import java.awt.*;
  import java.awt.event.*;

  public class JCottageFrame extends
  JFrame implements ItemListener {

     final int ONE_BEDROOM = 650;
     final int TWO_BEDROOM = 850;
     final int ROW_BOAT = 60;
     int totalPrice;

     ButtonGroup group = new ButtonGroup();

     JCheckBox oneBed = new JCheckBox
  ("One Bedroom/week $" + ONE_BEDROOM, false);

     JCheckBox twoBed = new
  JCheckBox("Two Bedroom/week $" + TWO_BEDROOM, false);
     JCheckBox boat = new JCheckBox ("Boat/week $" + ROW_BOAT, false);

     JLabel resortLabel = new JLabel ("Koch's Cottages Weekly Rentals");
     JLabel priceLabel = new JLabel("The price for your stay is");

     JTextField totPrice = new JTextField(4);
     JLabel optionExplainLabel2 = new JLabel
  ("Check the rentals you wish to purchase.");


     public JCottageFrame() {

        super("JCottageFrame");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setLayout(new FlowLayout());

        add(resortLabel);
        add(optionExplainLabel2);
        group.add(oneBed);
        group.add(twoBed);
        add(group);  //This does not seem to be working correctly
        add(boat);
        add(priceLabel);
        add(totPrice);

        totPrice.setText("$" + totalPrice);

        oneBed.addItemListener(this);
        twoBed.addItemListener(this);
        boat.addItemListener(this);
     }
        public void itemStateChanged(ItemEvent event) {
        Object source = event.getSource();
        int select = event.getStateChange();

        if(source == oneBed)
        if(select == ItemEvent.SELECTED)
           totalPrice += ONE_BEDROOM;
           else
              totalPrice -= ONE_BEDROOM;
           else
              if(source == twoBed) {
              if(select == ItemEvent.SELECTED)
                 totalPrice += TWO_BEDROOM;
                    else
                       totalPrice -= TWO_BEDROOM;
              }
              else
                 if(select == ItemEvent.SELECTED)
                    totalPrice += ROW_BOAT;
                    else
                       totalPrice -= ROW_BOAT;
                       totPrice.setText("$" + totalPrice);
        }

        public static void main(String[] args)
  {
           JCottageFrame aFrame =
  new JCottageFrame();
           final int WIDTH = 270;
           final int HEIGHT = 230;
           aFrame.setSize(WIDTH, HEIGHT);
           aFrame.setVisible(true);

           aFrame.setLocationRelativeTo(null);
  }
  }

Receiving a "no suitable method found for add(ButtonGroup)," though I did declare it.

Answer 1

You don't add the ButtonGroup to the frame. You add the radio buttons to the group to indicate what the possible options are. You add the buttons to the frame to indicate where they should appear. These are independent concerns. (Source).

Additionally, using JRadioButton instead of JCheckBox will provide the user a better indication that only one can be selected.