I$\text{'}$m having trouble with running this program. The info is shared below.

package project$3$;

import java.awt.$*$;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JFrame;

import tripcost.TripCost;

public class Project$3$ extends JFrame $\{$

private final JTextField totalTripCostTxt;

private boolean isMiles;

private boolean isDolPerGallon;

private boolean isMilesPerGallon;

public Project$3()\{$

setVisible$("$Trip Cost Estimator"$)$;

setSize$(400,400)$;

setDefaultCloseOperation$($JFrame$.$DISPOSE$\_$ON$\_$CLOSE$)$;

setLayout$($new GridLayout$(9,3,5,5))$;

$//$ Initialize the components

add$($new JLabel$("$Distance:$"))$;

JTextField distanceTxt $=$ new JTextField$()$;

distanceTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($distanceTxt$)$;

isMiles $=$ true;

JComboBox distanceUnitCmbx $=$ new JComboBoxnew String$[]\{"$miles$",$ "kilometers"$\})$;

distanceUnitCmbx.addActionListener$($a $->$

isMiles $=$ distanceUnitCmbx.getSelectedItem$().$equals$("$miles$"))$;

add$($distanceUnitCmbx$)$;

add$($new JLabel$("$Gasoline Cost:"$))$;

JTextField gasCostTxt $=$ new JTextField$()$;

gasCostTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($gasCostTxt$)$;

isDolPerGallon $=$ true;

JComboBox gasolineCostUnitComboBox $=$ new JComboBoxnew String$[]\{"$dollars$/$gal$",$ "dollars$/$liter$"\})$;

gasolineCostUnitComboBox.addActionListener$($a $->$

isDolPerGallon $=$ gasolineCostUnitComboBox.getSelectedItem$().$equals$("$dollars$/$gal$"))$;

add$($gasolineCostUnitComboBox$)$;

JLabel gasMileageLbl $=$ new JLabel$("$Gas Mileage"$)$;

add$($gasMileageLbl$)$;

JTextField gasMilTxt $=$ new JTextField$()$;

gasMilTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($gasMilTxt$)$;

isMilesPerGallon $=$ true;

JComboBox gasMileageUnitComboBox $=$ new JComboBoxnew String$[]\{"$miles$/$gallon$","$km$/$liter$"\})$;

gasMileageUnitComboBox.addActionListener$($a $->$

isMilesPerGallon $=$ gasMileageUnitComboBox.getSelectedItem$().$equals$("$miles$/$gallon$"))$;

add$($gasMileageUnitComboBox$)$;

add$($new JLabel$("$Number Of Days:"$))$;

JTextField numberOfDays $=$ new JTextField$()$;

numberOfDays.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($numberOfDays$)$;

add$($new JLabel$())$; $//$ empty space

add$($new JLabel$("$Hotel Cost"$))$;

JTextField hotelCostTxt $=$ new JTextField$()$;

hotelCostTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($hotelCostTxt$)$;

add$($new JLabel$())$; $//$ empty space

add$($new JLabel$("$Food Cost"$))$;

JTextField foodCostTxt $=$ new JTextField$()$;

foodCostTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($foodCostTxt$)$;

add$($new JLabel$())$; $//$ empty space

add$($new JLabel$("$Attractions Cost"$))$;

JTextField attractionsCostTxt $=$ new JTextField$()$;

attractionsCostTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

add$($attractionsCostTxt$)$;

add$($new JLabel$())$; $//$ empty space

add$($new JLabel$())$; $//$ empty space

JButton calculateButton $=$ new JButton$("$Calculate$")$;

calculateButton.addActionListener$($new ActionListener$()\{$

@Override

public void actionPerformed$($ActionEvent e$)\{$

try $\{$

double distance $=$ Double.parseDouble$($distanceTxt$.$getText$())$;

double gasolineCost $=$ Double.parseDouble$($gasCostTxt$.$getText$())$;

double gasMileage $=$ Double.parseDouble$($gasMilTxt$.$getText$())$;

double hotelCost $=$ Double.parseDouble$($hotelCostTxt$.$getText$())$;

double foodCost $=$ Double.parseDouble$($foodCostTxt$.$getText$())$;

double attractionsCost $=$ Double.parseDouble$($attractionsCostTxt$.$getText$())$;

int numOfDays $=$ Integer.parseInt$($numberOfDays$.$getText$())$;

TripCost tripCost $=$ new TripCost$($distance$,$ gasolineCost, gasMileage, hotelCost,

foodCost, numOfDays, attractionsCost, isMiles, isDolPerGallon, isMilesPerGallon$)$;

totalTripCostTxt.setText$($String$.$format$("$$$\%\mathrm{.}2$f$",$ tripCost.calculateTotalCost$()))$;

$\}$ catch $($NumberFormatException ex$)\{$

JOptionPane.showMessageDialog$($null$,$ "Invalid input. Please enter valid numbers.", "Error", JOptionPane.ERROR$\_$MESSAGE$)$;

$\}$

$\}$

$\})$;

add$($calculateButton$)$;

add$($new JLabel$())$; $//$ empty space

add$($new JLabel$("$Total Trip Cost"$))$;

totalTripCostTxt $=$ new JTextField$("0\mathrm{.}0")$;

totalTripCostTxt.setHorizontalAlignment$($SwingConstants$.$RIGHT$)$;

totalTripCostTxt.setEditable$($false$)$;

add$($totalTripCostTxt$)$;

$\}$

public static void main$($String$[]$ args$)\{$

SwingUtilities.invokeLate

$($It is supposed to display the image below$)$

Please Help. Thank you!