Attack.java

// Two attacks on the internals of an "immutable" period
package org.effectivejava.examples.chapter07.item39;

import java.util.Date;

public class Attack {
	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);
	}
}