// These contain bytes not in the decodabet.
    assertFailsToDecode(base64(), "A\u007f", "Unrecognized character: 0x7f");
    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");

    // These contain bytes not in the decodabet.
    assertFailsToDecode(base64(), "A\u007f", "Unrecognized character: 0x7f");
    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");

 *       differ significantly. And sometimes testcases cover multiple methods when they cannot be
 *       tested in isolation.
 *   <li>The documentation style for testcases is to provide as javadoc a simple sentence or two
 *       describing the property that the testcase method purports to test. The javadocs do not say
 *       anything about how the property is tested. To find out, read the code.

 *       differ significantly. And sometimes testcases cover multiple methods when they cannot be
 *       tested in isolation.
 *   <li>The documentation style for testcases is to provide as javadoc a simple sentence or two
 *       describing the property that the testcase method purports to test. The javadocs do not say
 *       anything about how the property is tested. To find out, read the code.

   * java.util.stream.Stream#filter}. This method is not being deprecated, but we gently encourage
   * you to migrate to streams.
   */
  // TODO(kevinb): how to omit that last sentence when building GWT javadoc?
  public static <E extends @Nullable Object> Set<E> filter(
      Set<E> unfiltered, Predicate<? super E> predicate) {
    if (unfiltered instanceof SortedSet) {

   * Returns the number of bytes in the UTF-8-encoded form of {@code sequence}. For a string, this
   * method is equivalent to {@code string.getBytes(UTF_8).length}, but is more efficient in both
   * time and space.
   *
   * @throws IllegalArgumentException if {@code sequence} contains ill-formed UTF-16 (unpaired
   *     surrogates)
   */
  public static int encodedLength(CharSequence sequence) {

   * characters which constitute a machine-sensible address or routing information. Such a sequence
   * is referred to as the "heading." An STX character has the effect of terminating a heading.
   *
   * @since 8.0
   */
  public static final byte SOH = 1;

  /**
   * Start of Text: A communication control character which precedes a sequence of characters that

    assertThrows(IOException.class, () -> reader.reset());
  }

  /**
   * Creates a CharSequenceReader wrapping the given CharSequence and tests that the reader produces
   * the same sequence when read using each type of read method it provides.
   */
  private static void assertReadsCorrectly(CharSequence charSequence) throws IOException {
    String expected = charSequence.toString();

   * Preconditions} class use this formatter, for both of the reasons just discussed.
   *
   * <p><b>Warning:</b> Only the exact two-character placeholder sequence {@code "%s"} is
   * recognized.
   *
   * @param template a string containing zero or more {@code "%s"} placeholder sequences. {@code
   *     null} is treated as the four-character string {@code "null"}.

   * sequence. Returns a bogus matcher if the sequence contains supplementary characters.
   */
  public static CharMatcher anyOf(final CharSequence sequence) {
    switch (sequence.length()) {
      case 0:
        return none();
      case 1:
        return is(sequence.charAt(0));
      case 2:
        return isEither(sequence.charAt(0), sequence.charAt(1));
      default: