final int length) {
        final HMACT64 hmac = new HMACT64(responseKey);
        hmac.update(serverChallenge);
        hmac.update(clientData, offset, length);
        final byte[] mac = hmac.digest();
        final byte[] ret = new byte[mac.length + clientData.length];
        System.arraycopy(mac, 0, ret, 0, mac.length);

        assertNotNull(types);
        assertEquals(0, types.length);

        fileTypeHelper.add("application/pdf", "pdf");
        fileTypeHelper.add("text/plain", "text");
        fileTypeHelper.add("image/jpeg", "image");

        types = fileTypeHelper.getTypes();
        assertEquals(3, types.length);

        Arrays.sort(types);
        assertEquals("image", types[0]);

    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  protected abstract Collection<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {
    return new String[length];
  }

  /** Returns the original element list, unchanged. */

    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  protected abstract Queue<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {
    return new String[length];
  }

  /** Returns the original element list, unchanged. */
  @Override

    public Entry<Country, String>[] createArray(int length) {
      return (Entry<Country, String>[]) new Entry<?, ?>[length];
    }

    @Override
    public Iterable<Entry<Country, String>> order(List<Entry<Country, String>> insertionOrder) {
      return insertionOrder;
    }

    @Override
    public Country[] createKeyArray(int length) {
      return new Country[length];
    }

    @Override

            final Extractor[] existingExtractors = extractorMap.get(key);

            final Extractor[] newExtractors = new Extractor[existingExtractors.length + 1];
            System.arraycopy(existingExtractors, 0, newExtractors, 0, existingExtractors.length);
            newExtractors[newExtractors.length - 1] = extractor;

            Arrays.sort(newExtractors, Comparator.comparingInt(Extractor::getWeight).reversed());

      checkArgument(
          nextBytes.length == resultBytes.length, "All hashcodes must have the same bit length.");
      for (int i = 0; i < nextBytes.length; i++) {
        resultBytes[i] = (byte) (resultBytes[i] * 37 ^ nextBytes[i]);
      }
    }
    return HashCode.fromBytesNoCopy(resultBytes);
  }

  /**
   * Returns a hash code, having the same bit length as each of the input hash codes, that combines

   * #create(Object...)}.
   */
  protected abstract List<Character> create(Character[] elements);

  @Override
  public Character[] createArray(int length) {
    return new Character[length];
  }

  /** Returns the original element list, unchanged. */
  @Override
  public List<Character> order(List<Character> insertionOrder) {
    return insertionOrder;
  }

   * #create(Object...)}.
   */
  protected abstract T create(UnhashableObject[] elements);

  @Override
  public UnhashableObject[] createArray(int length) {
    return new UnhashableObject[length];
  }

  @Override
  public Iterable<UnhashableObject> order(List<UnhashableObject> insertionOrder) {
    return insertionOrder;
  }

   * #create(Object...)}.
   */
  protected abstract List<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {
    return new String[length];
  }

  /** Returns the original element list, unchanged. */
  @Override
  public List<String> order(List<String> insertionOrder) {
    return insertionOrder;
  }