Passwort-Pruefer-Profis/src/Main.java

import java.io.InputStream;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
       if(login(System.in)) {
           System.out.println("Hello World");
       }
    }

    public static boolean login(InputStream in) {
        Scanner s = new Scanner(in);


        for (int i = 0; i < 3; i++) {
            System.out.print("Benutzername: ");
            String login = s.next();
            System.out.print("Passwort: ");
            String passwort = s.next();

            Credentials cred = new Credentials(login, passwort);

            if (cred.valid()) {
                return true;
            }

            System.out.println("Du kommst hier nicht rein");
        }
        s.close();
        return false;
    }
}