How To Transform Code To Save Room Booking Into TXT File

I am doing the home work to create a mini hotel reservation system which should be able to write the data into .txt file.

case study:

1. Have 2 different types of room (1- Suite 2- Deluxe)

2. Room Rate (Suite - $500per night, Deluxe - $300per night)

3. Both rooms can accomodate 2adults and 2childs

4. Checkin time: 2pm, Checkout 11am

5. Room status = occupied once guest checkin, Room status = vacant once guest checkout

6.For checking require (ID,Full Name,Address,Nationality,Flight no/Vehicle Reg no,number of people,check-in date, check-out-date,payment detail

7.Front desk search the vacant room to be assigned to the guest

Functions:

1. View all rooms
2. Add Customer to a room
3. Display available room
4. Delete customer from a room
5. Find room from customer name
6. Exit

Files:

One file use to store room info. (to be retrieved by program)

One file use to store rate info. (to be retrieve by program)

One file use to store the booking details (to be created and write by the program).

Currently I have write a program but only compiling and display the output to the console. How to modify my code below to be able to save to the .txt file

Here is the code:

import java.util.*;
import java.io.*;
class Customer {
private String name;
private int room;
public void setName(String name) {
this.name=name;

[code]...