public static final CharMatcher OLD_WHITESPACE =
      new CharMatcher() {
        @Override
        public boolean matches(char c) {
          return OLD_WHITESPACE_TABLE.charAt(c % 79) == c;
        }
      };

  @Param private boolean useNew;

  @Param({"20", "50", "80"})
  private int percentMatching;

  private String teststring;
  private CharMatcher matcher;

    checkNotNull(a);
    checkNotNull(b);

    int maxPrefixLength = Math.min(a.length(), b.length());
    int p = 0;
    while (p < maxPrefixLength && a.charAt(p) == b.charAt(p)) {
      p++;
    }
    if (validSurrogatePairAt(a, p - 1) || validSurrogatePairAt(b, p - 1)) {
      p--;
    }
    return a.subSequence(0, p).toString();
  }

  /**

    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.
    while (i < utf16Length && sequence.charAt(i) < 0x80) {
      i++;
    }

    // This loop optimizes for chars less than 0x800.
    for (; i < utf16Length; i++) {
      char c = sequence.charAt(i);
      if (c < 0x800) {
        utf8Length += ((0x7f - c) >>> 31); // branch free!
      } else {

    if (s1 == s2) {
      return true;
    }
    if (length != s2.length()) {
      return false;
    }
    for (int i = 0; i < length; i++) {
      char c1 = s1.charAt(i);
      char c2 = s2.charAt(i);
      if (c1 == c2) {
        continue;
      }
      int alphaIndex = getAlphaIndex(c1);
      // This was also benchmarked using '&' to avoid branching (but always evaluate the rhs),

    if (stringValue.length() == 0) {
      throw new NumberFormatException("empty string");
    }

    // Handle radix specifier if present
    String rawValue;
    int radix;
    char firstChar = stringValue.charAt(0);
    if (stringValue.startsWith("0x") || stringValue.startsWith("0X")) {
      rawValue = stringValue.substring(2);
      radix = 16;
    } else if (firstChar == '#') {
      rawValue = stringValue.substring(1);

   */
  @Override
  public final String escape(String s) {
    checkNotNull(s); // GWT specific check (do not optimize)
    for (int i = 0; i < s.length(); i++) {
      char c = s.charAt(i);
      if ((c < replacementsLength && replacements[c] != null)
          || c > safeMaxChar
          || c < safeMinChar) {
        return escapeSlow(s, i);
      }
    }
    return s;
  }

      new Function<@Nullable String, @Nullable Character>() {
        @Override
        public @Nullable Character apply(@Nullable String input) {
          return input == null ? null : input.charAt(0);
        }
      };

  @Override
  protected Table<String, Integer, Character> create(@Nullable Object... data) {
    Table<String, Integer, String> table = HashBasedTable.create();

    }
  }

  private static class DontStringMeBro implements CharSequence {
    @Override
    public int length() {
      return 3;
    }

    @Override
    public char charAt(int index) {
      return "foo".charAt(index);
    }

    @Override
    public CharSequence subSequence(int start, int end) {
      return "foo".subSequence(start, end);
    }

    @Override

    String expected = charSequence.toString();

    // read char by char
    CharSequenceReader reader = new CharSequenceReader(charSequence);
    for (int i = 0; i < expected.length(); i++) {
      assertEquals(expected.charAt(i), reader.read());
    }
    assertFullyRead(reader);

    // read all to one array
    reader = new CharSequenceReader(charSequence);
    char[] buf = new char[expected.length()];

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()