return Maps.newTreeMap();
  }

  public void testFirstAndLastKeyFilteredMap() {
    SortedMap<String, Integer> unfiltered = createUnfiltered();
    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());

        doc.put("key1", new String[] { "aaa", "bbb" });
        assertArrayEquals(new String[] { "aaa", "bbb" }, DocumentUtil.getValue(doc, "key1", String[].class));
        assertEquals(Arrays.asList("aaa", "bbb"), (List<String>) DocumentUtil.getValue(doc, "key1", List.class));
    }

    public void test_list() {
        Map<String, Object> doc = new HashMap<>();
        doc.put("key1", Arrays.asList("aaa", "bbb"));

    return (ConcurrentMap<K, V>) super.getMap();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testReplaceEntry_supportedPresent() {
    assertTrue(getMap().replace(k0(), v0(), v3()));
    expectReplacement(entry(k0(), v3()));
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testReplaceEntry_supportedPresentUnchanged() {

    return Maps.newTreeMap();
  }

  public void testFirstAndLastKeyFilteredMap() {
    SortedMap<String, Integer> unfiltered = createUnfiltered();
    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());

    return (ConcurrentMap<K, V>) super.getMap();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutIfAbsent_supportedAbsent() {
    assertNull("putIfAbsent(notPresent, value) should return null", putIfAbsent(e3()));
    expectAdded(e3());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutIfAbsent_supportedPresent() {
    assertEquals(

        TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    multimap.put("google", 2);
    multimap.put("google", 6);
    multimap.put(null, 3);
    multimap.put(null, 1);
    multimap.put(null, 7);
    multimap.put("tree", 0);
    multimap.put("tree", null);
    return multimap;
  }

  /** Test that a TreeMultimap created from another uses the natural ordering. */

            defaultMap.put(FessConfig.API_GSA_RESPONSE_HEADERS, "");
            defaultMap.put(FessConfig.API_GSA_RESPONSE_EXCEPTION_INCLUDED, "false");
            defaultMap.put(FessConfig.API_DASHBOARD_RESPONSE_HEADERS, "");
            defaultMap.put(FessConfig.API_CORS_ALLOW_ORIGIN, "*");
            defaultMap.put(FessConfig.API_CORS_ALLOW_METHODS, "GET, POST, OPTIONS, DELETE, PUT");

    for (String row : elements) {
      table.put(row, 1, 'a');
      table.put(row, 2, 'b');
    }
  }

  private static void populateForColumnKeySet(
      Table<Integer, String, Character> table, String[] elements) {
    for (String column : elements) {
      table.put(1, column, 'a');
      table.put(2, column, 'b');
    }
  }

  private static void populateForValues(

        ImmutableBiMap.<String, String>builder()
            .put("CDN_LOOP", "CDN-Loop")
            .put("ETAG", "ETag")
            .put("SOURCE_MAP", "SourceMap")
            .put("SEC_CH_UA_WOW64", "Sec-CH-UA-WoW64")
            .put("SEC_WEBSOCKET_ACCEPT", "Sec-WebSocket-Accept")
            .put("SEC_WEBSOCKET_EXTENSIONS", "Sec-WebSocket-Extensions")
            .put("SEC_WEBSOCKET_KEY", "Sec-WebSocket-Key")

    mJapaneseToInteger.put("Ichi", 1);
    mJapaneseToInteger.put("Ni", 2);
    mJapaneseToInteger.put("San", 3);
    Function<String, Integer> japaneseToInteger = Functions.forMap(mJapaneseToInteger);

    Map<Integer, String> mIntegerToSpanish = Maps.newHashMap();
    mIntegerToSpanish.put(1, "Uno");
    mIntegerToSpanish.put(3, "Tres");
    mIntegerToSpanish.put(4, "Cuatro");