StringBuilder sb = new StringBuilder();
      for (int j = 0; j < charCount; j++) {
        int codePoint;
        // discard illegal surrogate "codepoints"
        do {
          codePoint = rnd.nextInt(maxCodePoint.value);
        } while (Character.isSurrogate((char) codePoint));
        sb.appendCodePoint(codePoint);
      }
      strings[i] = sb.toString();
    }
  }

  @Benchmark

        utf8Length += (0x7f - c) >>> 31; // branch free!
      } else {
        utf8Length += 2;
        // We can't use Character.isSurrogate(c) here and below because of GWT.
        if (MIN_SURROGATE <= c && c <= MAX_SURROGATE) {
          // Check that we have a well-formed surrogate pair.
          if (Character.codePointAt(sequence, i) == c) {
            throw new IllegalArgumentException(unpairedSurrogateMsg(i));
          }

      MAX_LOW_SURROGATE, MAX_HIGH_SURROGATE, MIN_LOW_SURROGATE, MIN_HIGH_SURROGATE,
    };
    for (char surrogate : surrogates) {
      builder.add(newString(surrogate));
      builder.add(newString(surrogate, 'n'));
      builder.add(newString('n', surrogate));
      builder.add(newString(surrogate, surrogate));
    }
    builder.add(newString(MIN_LOW_SURROGATE, MAX_HIGH_SURROGATE));
    ILL_FORMED_STRINGS = builder.build();
  }

   * Specifically "\r" (carriage return) is preserved in the output, which may result in it being
   * silently converted to "\n" when the XML is parsed.
   *
   * <p>This escaper does not treat surrogate pairs specially and does not perform Unicode
   * validation on its input.
   */
  public static Escaper xmlContentEscaper() {
    return XML_CONTENT_ESCAPER;
  }

  /**

    assertEquals("abc", Strings.commonPrefix(new StringBuilder("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(
        "abc\uD8AB\uDCAB", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
    // Differing valid surrogate pairs.
    assertEquals("abc", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCACxyz"));
    // One invalid pair.

    // Build up a range of surrogate pair characters to test
    int min = Character.MIN_SUPPLEMENTARY_CODE_POINT;
    int max = Character.MAX_CODE_POINT;
    int range = max - min;
    int s1 = min + (1 * range) / 4;
    int s2 = min + (2 * range) / 4;
    int s3 = min + (3 * range) / 4;
    char[] dst = new char[12];

    // Put surrogate pairs at odd indices so they can be split easily

    // Build up a range of surrogate pair characters to test
    int min = Character.MIN_SUPPLEMENTARY_CODE_POINT;
    int max = Character.MAX_CODE_POINT;
    int range = max - min;
    int s1 = min + (1 * range) / 4;
    int s2 = min + (2 * range) / 4;
    int s3 = min + (3 * range) / 4;
    char[] dst = new char[12];

    // Put surrogate pairs at odd indices so they can be split easily

    return new String(array);
  }

  /**
   * Returns the longest string {@code prefix} such that {@code a.toString().startsWith(prefix) &&
   * b.toString().startsWith(prefix)}, taking care not to split surrogate pairs. If {@code a} and
   * {@code b} have no common prefix, returns the empty string.
   *
   * @since 11.0
   */
  public static String commonPrefix(CharSequence a, CharSequence b) {
    checkNotNull(a);

   * for use with it (such as all-ASCII text) and for simple debugging text. When using this method,
   * consider the following:
   *
   * <ul>
   *   <li>it may split surrogate pairs
   *   <li>it may split characters and combining characters
   *   <li>it does not consider word boundaries
   *   <li>if truncating for display to users, there are other considerations that must be taken

    }
  }

  /**
   * This verifies that putUnencodedChars(String) and hashUnencodedChars(String) are equivalent,
   * even for funny strings composed by (possibly unmatched, and mostly illegal) surrogate
   * characters. (But doesn't test that they do the right thing - just their consistency).
   */
  private static void assertHashStringWithSurrogatesEquivalence(
      HashFunction hashFunction, Random random) {