private static void checkContract(final BaseCloneable original, final BaseCloneable clone) {
    System.out.println("Original: " + original);
    System.out.println("Kopie: " + clone);

    // Kontraktprüfung
    System.out.println("\nKontraktprüfung:");
    System.out.println("Objekterzeugung? " + (clone != original));
    System.out.println("Typgleichheit?   " + clone.getClass().equals(original.getClass()));
    System.out.println("Wertgleichheit?  " + clone.equals(original));
  }