} catch (NullPointerException expected) {
    }
    try {
      table.put("cat", null, cellValue('d'));
      fail();
    } catch (NullPointerException expected) {
    }
    if (supportsNullValues()) {
      assertNull(table.put("cat", 2, null));
      assertTrue(table.contains("cat", 2));
    } else {
      try {
        table.put("cat", 2, null);
        fail();
      } catch (NullPointerException expected) {
      }

    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Table<String, Integer, Character> other = HashBasedTable.create();
    other.put("foo", 1, 'd');
    other.put("bar", 2, 'e');
    other.put("cat", 2, 'f');
    try {
      table.putAll(other);
      fail("Expected UnsupportedOperationException");
    } catch (UnsupportedOperationException expected) {
    }
    assertEquals((Character) 'a', table.get("foo", 1));

  @Override
  protected Table<String, Integer, Character> create(@Nullable Object... data) {
    Table<String, Integer, Character> table = HashBasedTable.create();
    table.put("foo", 4, 'a');
    table.put("cat", 1, 'b');
    table.clear();
    populate(table, data);
    return table;
  }

  public void testIterationOrder() {
    Table<String, String, String> table = HashBasedTable.create();

    } catch (NullPointerException expected) {
    }
    try {
      table.put("cat", null, cellValue('d'));
      fail();
    } catch (NullPointerException expected) {
    }
    if (supportsNullValues()) {
      assertNull(table.put("cat", 2, null));
      assertTrue(table.contains("cat", 2));
    } else {
      try {
        table.put("cat", 2, null);
        fail();
      } catch (NullPointerException expected) {
      }

    assertTrue(table.contains("bar", 1));
    assertTrue(table.contains("foo", 3));
    assertFalse(table.contains("foo", 2));
    assertFalse(table.contains("bar", 3));
    assertFalse(table.contains("cat", 1));
    assertFalse(table.contains("foo", null));
    assertFalse(table.contains(null, 1));
    assertFalse(table.contains(null, null));
  }

  public void testContainsRow() {

    assertTrue(table.contains("bar", 1));
    assertTrue(table.contains("foo", 3));
    assertFalse(table.contains("foo", 2));
    assertFalse(table.contains("bar", 3));
    assertFalse(table.contains("cat", 1));
    assertFalse(table.contains("foo", null));
    assertFalse(table.contains(null, 1));
    assertFalse(table.contains(null, null));
  }

  public void testContainsRow() {

  protected Map<String, Map<Integer, Character>> makePopulatedMap() {
    Table<String, Integer, String> table = HashBasedTable.create();
    table.put("foo", 1, "apple");
    table.put("bar", 1, "banana");
    table.put("foo", 3, "cat");
    return Tables.transformValues(table, TableCollectionTest.FIRST_CHARACTER).rowMap();
  }

    unfiltered.put("apple", 2);
    unfiltered.put("banana", 6);
    unfiltered.put("cat", 3);
    unfiltered.put("dog", 5);

    SortedMap<String, Integer> filtered = Maps.filterEntries(unfiltered, CORRECT_LENGTH);
    assertEquals("banana", filtered.firstKey());
    assertEquals("cat", filtered.lastKey());
  }

  public void testHeadSubTailMap_FilteredMap() {

  protected Map<String, Map<Integer, Character>> makePopulatedMap() {
    Table<Integer, String, String> table = HashBasedTable.create();
    table.put(1, "foo", "apple");
    table.put(1, "bar", "banana");
    table.put(3, "foo", "cat");
    return Tables.transformValues(table, FIRST_CHARACTER).columnMap();
  }

    for (int i = 0; i < length; i++) {
      checkElementNotNull(array[i], i);
    }
    return array;
  }

  // We do this instead of Preconditions.checkNotNull to save boxing and array
  // creation cost.
  @CanIgnoreReturnValue
  static Object checkElementNotNull(@CheckForNull Object element, int index) {
    if (element == null) {
      throw new NullPointerException("at index " + index);
    }
    return element;