package org.apidesign.cloneproblem;

 import java.util.Date;

 import junit.framework.TestCase;

 /** Test that would be written by the API hacker.

  *

  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  */

 public class ExploitTest extends TestCase {

     public ExploitTest(String name) {

         super(name);

     }

     public void testExploitOverridableClone() {

         try {

             HackedDate now = new HackedDate();

             HackedDate later = new HackedDate(now.getTime() + 1000);

             Interval interval = new Interval(now, later);

             assertEquals("1s", 1000, interval.getLength());

             fail("And I hoped NullPointerException will be thrown!");

         }  catch (NullPointerException ex) {

             // success, the quest is to generate NullPointerException!

         }

     }

     // BEGIN: interval.exploit

     private static class HackedDate extends Date {

         public HackedDate() {

         }

         public HackedDate(long date) {

             super(date);

         }

         @Override

         public Object clone() {

             return null;

         }

     }

     // END: interval.exploit

 }