import javax.swing.*;

public class BBH_GreetingPanel extends JPanel {
private JLabel greeting;

public BBH_GreetingPanel() {
    greeting = new JLabel("Welcome to Brandi's Bagel House!");

    add(greeting);
    }
}

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

public class BBH_ToppingPanel extends JPanel {
    public final double CREAM_CHEESE = 0.50;
    public final double BUTTER = 0.25;
    public final double PEACH_JELLY = 0.75;
    public final double BLUEBERRY_JAM = 0.75;

private JCheckBox creamCheese;
private JCheckBox butter;
private JCheckBox peachJelly;
private JCheckBox blueberryJam;

public BBH_ToppingPanel() {
    setLayout(new GridLayout(4, 1));

    creamCheese = new JCheckBox("Cream Cheese");
    butter = new JCheckBox("Butter");
    peachJelly = new JCheckBox("Peach Jelly");
    blueberryJam = new JCheckBox("Blueberry Jam");

    setBorder(BorderFactory.createTitledBorder("Toppings"));

    add(creamCheese);
    add(butter);
    add(peachJelly);
    add(blueberryJam);
}

public double getToppingCost() {
    double toppingCost = 0.0;

    if(creamCheese.isSelected())
        toppingCost += CREAM_CHEESE;
    if(butter.isSelected());
        toppingCost += BUTTER;
    if(peachJelly.isSelected());
        toppingCost += PEACH_JELLY;
    if(blueberryJam.isSelected());
        toppingCost += BLUEBERRY_JAM;

    return toppingCost;
    }

}

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

public class BBH_CoffeePanel extends JPanel{

public final double NO_COFFEE = 0.0;
public final double REGULAR_COFFEE = 1.25;
public final double DECAF_COFFEE = 1.25;
public final double CAPPUCCINO = 2.00;

private JRadioButton noCoffee;
private JRadioButton regularCoffee;
private JRadioButton decafCoffee;
private JRadioButton cappuccino;
private ButtonGroup bg;

public BBH_CoffeePanel() {

    setLayout(new GridLayout(4, 1));

    noCoffee = new JRadioButton("None", true);
    regularCoffee = new JRadioButton("Regular");
    decafCoffee = new JRadioButton("Decaffeinated");
    cappuccino = new JRadioButton("Cappuccino");

    bg = new ButtonGroup();
    bg.add(noCoffee);
    bg.add(regularCoffee);
    bg.add(decafCoffee);
    bg.add(cappuccino);

    setBorder(BorderFactory.createTitledBorder("Coffee"));

    add(noCoffee);
    add(regularCoffee);
    add(decafCoffee);
    add(cappuccino);

}

public double getCoffeeCost() {
    double coffeeCost = 0.0;

    if (noCoffee.isSelected())
        coffeeCost = NO_COFFEE;
    else if (regularCoffee.isSelected())
        coffeeCost = REGULAR_COFFEE;
    else if (decafCoffee.isSelected())
        coffeeCost = DECAF_COFFEE;
    else if (cappuccino.isSelected())
        coffeeCost = CAPPUCCINO;


    return coffeeCost;
    }

}

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



public class BBH_OrderCalc extends JFrame {
private BBH_BagelPanel bagels;
private BBH_ToppingPanel toppings;
private BBH_CoffeePanel coffee;
private BBH_GreetingPanel banner;
private JPanel buttonPanel;
private JButton calcButton;
private JButton exitButton;
private final double TAX_RATE = 0.06;

public BBH_OrderCalc() {

    setTitle("BBH Order Calculator");

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    setLayout(new BorderLayout());

    banner = new BBH_GreetingPanel();
    bagels = new BBH_BagelPanel();
    toppings = new BBH_ToppingPanel();
    coffee = new BBH_CoffeePanel();

    buildButtonPanel();

    add(banner, BorderLayout.NORTH);
    add(bagels, BorderLayout.WEST);
    add(toppings, BorderLayout.CENTER);
    add(coffee, BorderLayout.EAST);
    add(buttonPanel, BorderLayout.SOUTH);

    pack();
    setVisible(true);


}

private void buildButtonPanel() {

    buttonPanel = new JPanel();

    calcButton = new JButton("Calculate Order");
    exitButton = new JButton("Exit");

    calcButton.addActionListener(new CalcButtonListener());
    exitButton.addActionListener(new ExitButtonListener()); //Error present

    buttonPanel.add(calcButton);
    buttonPanel.add(exitButton);

}

private class CalcButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {

        double subtotal, tax, total;

        subtotal =  bagels.getBagelCost() +
                    toppings.getToppingCost() +
                    coffee.getCoffeeCost();

        tax = subtotal * TAX_RATE;

        total = subtotal + tax;

        JOptionPane.showMessageDialog(null,
            String.format("Subtotal: $%,.2fn" +
                          "Tax: $%,.2fn" +
                          "Total: $%,.2f",
                          subtotal, tax, total));

            private class ExitButtonListener implements ActionListener {  //Error present
                public void actionPerformed(ActionEvent e) {
                    System.exit(0);
                }
            }

        }
    }

public static void main(String[] args) {
    new BBH_OrderCalc();

    }

}

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
    ExitButtonListener cannot be resolved to a type

    at BBH_OrderCalc.buildButtonPanel(BBH_OrderCalc.java:50)
    at BBH_OrderCalc.<init>(BBH_OrderCalc.java:28)
    at BBH_OrderCalc.main(BBH_OrderCalc.java:86)