public static String name = "User";
public static String password = "admin";

public static void main(String[] args){
    MinOppgave2 login = new MinOppgave2(); //MinOppgave2 is my class
    Scanner sc = new Scanner(System.in);
    boolean exists = true;
    System.out.print("Username: ");
    loginName = sc.nextLine();

    exists = login.check(loginName, false); //false => username

    System.out.print("Password: ");
    loginPassword = sc.nextLine();

    exists = login.check(loginPassword, true);  //true => password

}//end main

public boolean check(String fetch, boolean usernameOrPassword){
    boolean output = true;

    if (usernameOrPassword){
        //password
        if(fetch == password){
            output = true;
        }else{
            output = false;
        }
    }
    if (!usernameOrPassword){
        //username
        if(fetch == name){
            output = true;
        }else{
            output = false;
        }
    }
    return output;
}//end check