@Test
  public void testGetNotThere() {
    ObjIdMap map = new ObjIdMap();
    int key = 4;
    assertSame(null, map.get(key));
  }
This class tests the functionality of the {@link ObjIdMap} class.
geode-core/src/test/java/org/apache/geode/internal/ObjIdMapJUnitTest.java