Use a class in a switch statement

package bankapp;
import java.util.*;
import java.text.*;

class UserChoice{
    //Variables for logging in
    private String user, pass; //username and password where users type in
    private String username = "Kate", password = "abc456"; //username and password of the account
    
    //Variables for loan calculator
    private int amount, tenure; //the amount and duration of loan
    private double interest, MonthlyInterest; //the annual interest and monthly interest
    double payment; //monthly payment
    private int choose;
    
    //Variables for deposit & withfraw
    private int balance, Amount; //balance in the account & the amount of deposit/withdrawal
    private String acc, pin; //account number & PIN number
    private String AccNumber = "4344789", PinNumber = ""; //account number & PIN number of the account
    Scanner scanner = new Scanner(System.in);
    
    public void SignIn(){ //For logging in 
        System.out.println("Enter your username");
        user = scanner.next();
        System.out.println("Enter your password");
        pass = scanner.next();
        
    if ((user .equals(username)) && (pass .equals(password)))
        System.out.println("You've successfuly signed in");
    else
        System.out.println("Sign in details incorrect");
    }
    
    public void Loan(){ //Personal Loan and Housing Loan
        System.out.println("Enter the amount you want to borrow");
        amount = scanner.nextInt();
        
        System.out.println("Enter the tenure of your loan");
        tenure = scanner.nextInt();
        
        System.out.println("Enter the interest rate as a decimal");
        interest = scanner.nextDouble();
        
        MonthlyInterest = Math.pow(1+(interest/12), - tenure);
        payment = (amount * (interest/12)) / (1 - MonthlyInterest);
        DecimalFormat decimal = new DecimalFormat("##.##");
        
        System.out.println("This is the amount you have to pay monthly :" + decimal.format(payment));
        System.out.println("-------------------------------");
        System.out.println("Do you wish to apply for the loan \n1 Yes \n2 No");
        choose = scanner.nextInt();
        
        if (choose ==1)
            System.out.println("You have applied for the loan");
        else
            System.out.println("Your application have been cancelled.");
            
    }
    
    public void Deposit(){ //To deposit into account
        System.out.println("Enter account number");
        acc = scanner.next();
        
        if (acc .equals(AccNumber))
        {    System.out.println("Enter the amount you wish to deposit");
            amount = scanner.nextInt();
        }
        else
            System.out.println("Error: account number invalid");
    }
    
     public void withdraw(){ //To withdraw from account
        System.out.println("Enter pin number");
        pin = scanner.next();
        
        if (pin .equals (PinNumber))
        {
            System.out.println("How much would you like to withdraw ?");
            amount = scanner.nextInt();
        }
        else
            System.out.println("Error: Invalid PIN number");
    }

}

public class BankApp {

    public static void main(String[] args) {
       UserChoice choices = new UserChoice();
       
       System.out.println("What would you like to do ? \n1 Sign in \n2 Apply for a Personal Loan \n3 Apply for a Housing Loan \n4 Deposit \n5 Withdraw");
       switch (choices){
           case 1:
               choices.SignIn();
               break;
           case 2:
               choices.Loan();
               break;
           case 3:
               choices.Loan();
               break;
           case 4:
               choices.Deposit();
               break;
           case 5:
               choices.withdraw();
               break;
           default:
               System.out.println("Error: Invalid entry");
       }
       
    }
}