public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    String username;
    String password;
    System.out.println("Enter your username");
    username = input.nextLine();
    System.out.println("Enter your password");
    password = input.nextLine();
    UserList test2 = new UserList();
    if (test2.authenticate(username, password) == true) {
        System.out.println("Hi");
    } else {
        System.out.println("Username or/and password are wrong.");
    }
}

}

public class User {

protected String username;
protected String password;

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

public String getUsername() {
    return username;
}

public String getPassword() {
    return password;
}

@Override
public boolean equals(Object o) {
    if (o instanceof User) {
        return ((User) o).username.equals(username);
    }
    return false;
}

@Override
public int hashCode() {
    int hash = 7;
    hash = 97 * hash + Objects.hashCode(this.username);
    return hash;
}
}

public class UserList {

private HashSet<User> loginList;emphasized text

public UserList() {
    Scanner scan;
    loginList = new HashSet();
    try {
        scan = new Scanner(new File("src/boitedejeux/Logins.txt"));
        String ligne = scan.nextLine();
        while (scan.hasNext()) {
            ligne = scan.nextLine();
            String[] res = ligne.split(",");
            loginList.add(new User(res[0], (res[1])));
        }
    } catch (FileNotFoundException e) {
        System.out.println("Erreur");
    }
}

public boolean authenticate(String username, String password) {
    if (null == loginList) {
        throw new IllegalStateException("The user list isn't initialised");
    }

    return loginList.stream()
            .filter(usern -> usern.getUsername().equals(username))
            .filter(passw -> passw.getPassword().equals(password))
            .findFirst()
            .isPresent();
}
}

Test, Password
Test2, Password2