java- what causes the code to execute improbably

Question

I am writing a login code for a project I'm working on that includes CSV files. the code works fine if I put a constant value to File for example File = ("admins.csv"), but when I try to change the file depending on the input the program executes incorrectly.

The output comes out like this:

0-login as an Admin

1-login as a Librarian

0 Enter username: Enter password: admin false

login class:

import java.util.ArrayList;
import java.util.Scanner;  

public class Login {

public static Scanner sc = new Scanner(System.in);
private static ArrayList<User> users;
public static String File;

public static synchronized void readUsers(int x){
    
    switch (x) {
      case 0:
          File = ("admins.csv");
        break;
      case 1:
          File = ("libs.csv");
          break;
      default:
          File = ("admins.csv");
    } 
    
    if(null == users){
        users = new ArrayList<User>();
        Scanner scan = new Scanner (Login.class.getResourceAsStream(File));
        String line;
        while((scan.hasNextLine())){
            line=scan.nextLine();
            String[] tokens = line.split(",");
            users.add(new User(Integer.parseInt(tokens[0]), tokens[1], tokens[2]));
        }
        
    }
}
public static synchronized boolean find( String username, String password){
    if(null == users){
        throw new IllegalStateException("user list is not initialised");
    }

    return users.stream()
            .filter(u -> u.getUsername().equals(username))
            .filter(u -> u.getPassword().equals(password))
            .findFirst()
            .isPresent();
}



public static void main(String[] args) {
    
    try (Scanner sc = new Scanner(System.in)) {
        System.out.println("0-login as an Admin");
        System.out.println("1-login as an Librarian");

        int x= sc.nextInt();
                    
        readUsers(x);
        
        System.out.println("Enter username:");
        String name = sc.nextLine();
        
        System.out.println("Enter password:");
        String pass = sc.nextLine();
        

        
    if( find(name, pass)==true) {
        System.out.println("true");

    } else;
    System.out.println("false");
    
    }

}}

User class:

class User{

private int id;
private String username;
private String password;

public User(int id, String username, String password){
    this.id = id;
    this.username = username;
    this.password = password;
}

public int getId() {
    return id;
}

public String getUsername() {
    return username;
}

public String getPassword() {
    return password;
}

}

java- what causes the code to execute improbably

0 Answers0