public static void main(String[] args) { // Attack the internals of a Period instance - Page 185 Date start = new Date(); Date end = new Date(); Period p = new Period(start, end); end.setYear(78); // Modifies internals of p! System.out.println(p); // Second attack on the internals of a Period instance - Page 186 start = new Date(); end = new Date(); p = new Period(start, end); p.end().setYear(78); // Modifies internals of p! System.out.println(p); }