code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.tck;
  
  /*
   * Written by Doug Lea with assistance from members of JCP JSR-166
   * Expert Group and released to the public domain, as explained at
   * http://creativecommons.org/licenses/publicdomain
   */
  
  import junit.framework.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.io.*;
  
  public class EntryTest extends JSR166TestCase {
      public static void main(String[] args) {
          junit.textui.TestRunner.run (suite());
      }
      public static Test suite() {
          return new TestSuite(EntryTest.class);
      }
  
      static final String k1 = "1";
      static final String v1 = "a";
      static final String k2 = "2";
      static final String v2 = "b";
  
  
      /**
       * A new SimpleEntry(k, v) holds k, v.
       */
      public void testConstructor1() {
          Map.Entry e = new AbstractMap.SimpleEntry(k1, v1);
          assertEquals(k1, e.getKey());
          assertEquals(v1, e.getValue());
      }
  
      /**
       * A new SimpleImmutableEntry(k, v) holds k, v.
       */
      public void testConstructor2() {
          Map.Entry s = new AbstractMap.SimpleImmutableEntry(k1, v1);
          assertEquals(k1, s.getKey());
          assertEquals(v1, s.getValue());
      }
  
  
      /**
       * A new SimpleEntry(entry(k, v)) holds k, v.
       */
      public void testConstructor3() {
          Map.Entry e2 = new AbstractMap.SimpleEntry(k1, v1);
          Map.Entry e = new AbstractMap.SimpleEntry(e2);
          assertEquals(k1, e.getKey());
          assertEquals(v1, e.getValue());
      }
  
      /**
       * A new SimpleImmutableEntry(entry(k, v)) holds k, v.
       */
      public void testConstructor4() {
          Map.Entry s2 = new AbstractMap.SimpleImmutableEntry(k1, v1);
          Map.Entry s = new AbstractMap.SimpleImmutableEntry(s2);
          assertEquals(k1, s.getKey());
          assertEquals(v1, s.getValue());
      }
  
      /**
       * Entries with same key-value pairs are equal and have same
       * hashcodes
       */
      public void testEquals() {
          Map.Entry e2 = new AbstractMap.SimpleEntry(k1, v1);
          Map.Entry e = new AbstractMap.SimpleEntry(e2);
          Map.Entry s2 = new AbstractMap.SimpleImmutableEntry(k1, v1);
          Map.Entry s = new AbstractMap.SimpleImmutableEntry(s2);
          assertEquals(e2, e);
          assertEquals(e2.hashCode(), e.hashCode());
          assertEquals(s2, s);
          assertEquals(s2.hashCode(), s.hashCode());
          assertEquals(e2, s2);
          assertEquals(e2.hashCode(), s2.hashCode());
          assertEquals(e, s);
          assertEquals(e.hashCode(), s.hashCode());
      }
  
      /**
       * Entries with different key-value pairs are not equal
       */
      public void testNotEquals() {
          Map.Entry e2 = new AbstractMap.SimpleEntry(k1, v1);
          Map.Entry e = new AbstractMap.SimpleEntry(k2, v1);
          assertFalse(e2.equals( e));
          e = new AbstractMap.SimpleEntry(k1, v2);
          assertFalse(e2.equals( e));
          e = new AbstractMap.SimpleEntry(k2, v2);
          assertFalse(e2.equals( e));
  
          Map.Entry s2 = new AbstractMap.SimpleImmutableEntry(k1, v1);
          Map.Entry s = new AbstractMap.SimpleImmutableEntry(k2, v1);
          assertFalse(s2.equals( s));
          s = new AbstractMap.SimpleImmutableEntry(k1, v2);
          assertFalse(s2.equals( s));
          s = new AbstractMap.SimpleImmutableEntry(k2, v2);
          assertFalse(s2.equals( s));
      }
  
  
      /**
       * getValue returns last setValue for SimpleEntry
       */
      public void testSetValue1() {
          Map.Entry e2 = new AbstractMap.SimpleEntry(k1, v1);
          Map.Entry e = new AbstractMap.SimpleEntry(e2);
          assertEquals(k1, e.getKey());
          assertEquals(v1, e.getValue());
          e.setValue(k2);
          assertEquals(k2, e.getValue());
          assertFalse(e2.equals( e));
      }
  
      /**
       * setValue for SimpleImmutableEntry throws UnsupportedOperationException
       */
      public void testsetValue2() {
          Map.Entry s2 = new AbstractMap.SimpleImmutableEntry(k1, v1);
          Map.Entry s = new AbstractMap.SimpleImmutableEntry(s2);
          assertEquals(k1, s.getKey());
          assertEquals(v1, s.getValue());
          try {
              s.setValue(k2);
              shouldThrow();
          } catch (UnsupportedOperationException success) {}
      }
  }
  