import java.util.HashMap; import java.util.Map; public class Main { public static void main(String[] args) { Map phonebook = new HashMap(); TelephoneNumber a = new TelephoneNumber("01636280491"); phonebook.put(new Person("Martin", "Thoma"), a); phonebook.put(new Person("Max", "Mustermann"), a); System.out.println(phonebook); } }