jtulach@368: package org.apidesign.cloneproblem;
jtulach@368: 
jtulach@368: import java.util.Date;
jtulach@368: import junit.framework.TestCase;
jtulach@368: 
jtulach@368: /** Test that would be written by the API hacker.
jtulach@368:  *
jtulach@368:  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
jtulach@368:  */
jtulach@368: public class ExploitTest extends TestCase {
jtulach@368:     public ExploitTest(String name) {
jtulach@368:         super(name);
jtulach@368:     }
jtulach@368: 
jtulach@368:     public void testExploitOverridableClone() {
jtulach@368:         try {
jtulach@368:             HackedDate now = new HackedDate();
jtulach@368:             HackedDate later = new HackedDate(now.getTime() + 1000);
jtulach@368:             
jtulach@368:             Interval interval = new Interval(now, later);
jtulach@368:             assertEquals("1s", 1000, interval.getLength());
jtulach@368:             
jtulach@368:             fail("And I hoped NullPointerException will be thrown!");
jtulach@368:         }  catch (NullPointerException ex) {
jtulach@368:             // success, the quest is to generate NullPointerException!
jtulach@368:         }
jtulach@368:     }
jtulach@368: 
jtulach@368:     // BEGIN: interval.exploit
jtulach@368:     private static class HackedDate extends Date {
jtulach@368:         public HackedDate() {
jtulach@368:         }
jtulach@368: 
jtulach@368:         public HackedDate(long date) {
jtulach@368:             super(date);
jtulach@368:         }
jtulach@368: 
jtulach@368:         @Override
jtulach@368:         public Object clone() {
jtulach@368:             return null;
jtulach@368:         }
jtulach@368:     }
jtulach@368:     // END: interval.exploit
jtulach@368: }