FreeStyler Online Aparrels

package assignment;
import java.util.Scanner;
public class core{
    static Scanner input;
    int account;
    String username[];
    String password[];
    public static void main(String[] args) {
        int x = 0;
        boolean bool = true;
        core run = new core();
        run.readDat();
        do{
            switch (x) {

            case 0:
                input = new Scanner(System.in);
                x = mainMenu();
                break;
            case 1:
                x = run.admin();
                break;
            case 2:
                x = run.user();
                break;
            case 3:
                x = run.userLogin();
                break;
            case 4:
                x = run.userReg();
                break;
            default:
                bool = false;
                System.out.println(x);
                break;
            }
        } while (bool);
    }

    private static int mainMenu(){
        System.out.println("Welcome to FreeStyler Online Apparels");
        System.out.println("Login As:\n(1)Admin\n(2)User");
        boolean bool = true;
        String n;
        do {
            try{
                n = input.nextLine();
            } catch (Exception e) {
                System.out.println("Invalid input, " + e);
                System.out.println("Login As:\n(1)Admin\n(2)User");
                continue;
            }
            if (n.equals("1")){
                bool = false;
                return 1;
            }
            else if (n.equals("2")){
                bool = false;
                return 2;
            }
            else {
                System.out.println("Invalid input, please try again");
                System.out.println("Login As:\n(1)Admin\n(2)User");
                continue;
            }
        }while(bool);
        return 0;
    }
    private int admin(){
        boolean bool = true;
        String user, pass = null;
        do {
            System.out.println("-1 to back");
            System.out.print("Username: ");
            try {
                user = input.nextLine();
            } catch (Exception e){
                System.out.println("Error: " + e);
                continue;
            }
            if (backtrack(user)){
                bool = false;
                return 0;
            }
            System.out.print("Password: ");
            try{
                pass = input.nextLine();
            } catch (Exception e){
                System.out.println("Error: " + e);
            }

            if (backtrack(pass)){
                bool = false;
                return 0;
            }
            else if (user.equals("admin") && pass.equals("admin")){
                System.out.println("Login Successfully");
                bool = false;
                return 5;
            }
            else {
                System.out.println("Invalid username or password");
            }
        }while (bool);
        return 0;
    }

    private int user(){
        String x;
        System.out.println("-1 to back");
        System.out.println("(1)Login\n(2)Register");
        try{
        x = input.nextLine();
        }
        catch (Exception e){
            System.out.println("Invalid input, " + e);
            return 2;
        }

        if (x.equals("1")){
            return 3;
        }
        else if (x.equals("2")){
            return 4;
        }
        else if (x.equals("-1")){
            return 0;
        }
        else {
            System.out.println("Invalid input, please try again");
            return 0;
        }
    }

    private int userLogin(){
        boolean bool = true;
        String user, pass = null;

        do{
            System.out.println("-1 to back");
            System.out.print("Username: ");
            try {
                user = input.nextLine();
            } catch (Exception e){
                System.out.println("Error: " + e);
                continue;
            }
            if (user.equals("-1")){
                bool = false;
                return 2;
            }
            System.out.print("Password: ");
            try{
                pass = input.nextLine();
            } catch (Exception e){
                System.out.println("Error: " + e);
            }
            if (pass.equals("-1")){
                bool = false;
                return 2;
            }
            else {
                for (int i = 0; i < this.username.length; i++) {
                    if (user.equals(this.username[i]) && pass.equals(this.password[i])){
                        System.out.println("Login Successfully");
                        bool = false;
                        return 5;
                    }
                }
                System.out.println("Invalid username or password");
            }
        }while(bool);
        return 0;
    }

    private int userReg(){
        String user, pass;
        boolean bool = true;
        boolean taken;
        System.out.println("Register as");

        do{
            taken = false;
            System.out.print("Username: ");
            user = input.nextLine();

            for (int i = 0; i < this.username.length; i++) {
                if (user.equals(this.username[i])){
                    System.out.println("Username taken, please take different username");
                    taken = true;
                    continue;
                }
            }

            if (taken){
                continue;
            }

            else {
                System.out.println("Password: ");
                pass = input.nextLine();
                System.out.println("Account created successfully");
                bool = false;
                return 2;
            }
        }while(bool);
        return 0;
    }

    private void readDat(){
        readWrite io = new readWrite();
        io.openFile("login.txt"); //open and read file
        io.readFile();
        this.username = new String[io.user.size()];
        this.password = new String[io.pass.size()];
        for (int i = 0; i < this.password.length; i++) {
            this.username[i] = io.user.get(i);
            this.password[i] = io.pass.get(i);
        }
    }

    private boolean backtrack(String back){
        if (back.equals("-1")){
            return true;
        }
        else {
            return false;
        }
    }
}



package assignment;

import java.io.File;
import java.util.Formatter;
import java.util.Scanner;
import java.util.ArrayList;

public class readWrite {
    private Formatter x;
    private Scanner y;
    public ArrayList<String> user = new ArrayList<String>(1);
    public ArrayList<String> pass = new ArrayList<String>(1);

    public void createFile(String fileName){
        try {
            x = new Formatter(fileName);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }

    public void addRecord(String user, String pass){
        x.format("%s%s\n", user + " ", pass);
    }

    public void closeFile(){
        x.close();
    }

    public void openFile(String fileName){
        try {
            y = new Scanner(new File(fileName));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }

    public void readFile(){
        while(y.hasNext()){
            user.add(y.next());
            pass.add(y.next());
        }
    }

    public void closeRead(){
        y.close();
    }
}