@Test
  public void testIterator() {
    int size = 10;
    ObjIdMap map = new ObjIdMap();
    for (int i = 0; i < size; i++) {
      map.put(i, i);
    }
    assertEquals(size, map.size());

    boolean[] found = new boolean[size];

    ObjIdMap.EntryIterator iter = map.iterator();
    for (ObjIdMap.Entry e = iter.next(); e != null; e = iter.next()) {
      int key = e.key;
      // System.out.println(key);
      assertFalse("Already saw " + key, found[key]);
      found[key] = true;
    }

    for (int i = 0; i < found.length; i++) {
      assertTrue(i + " not found", found[i]);
    }

  }
This class tests the functionality of the {@link ObjIdMap} class.
geode-core/src/test/java/org/apache/geode/internal/ObjIdMapJUnitTest.java