* <p>If the implementation of this method cannot correctly handle a particular code point then it
   * should either throw an appropriate runtime exception or return a suitable replacement
   * character. It must never silently discard invalid input as this may constitute a security risk.
   *
   * @param cp the Unicode code point to escape if necessary
   * @return the replacement characters, or {@code null} if no escaping was needed
   */
  @CheckForNull

   * input is not modified. The returned list is serializable and has random access.
   *
   * <p>Unlike {@link Sets#newTreeSet(Iterable)}, this method does not discard elements that are
   * duplicates according to the comparator. The sort performed is <i>stable</i>, meaning that such
   * elements will appear in the returned list in the same order they appeared in {@code elements}.
   *

    strings = new String[SAMPLES];
    for (int i = 0; i < SAMPLES; i++) {
      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 = new String[SAMPLES];
    for (int i = 0; i < SAMPLES; i++) {
      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);
      }