for (int n = 0; n < length; n++) {
      builder.append(
          randomCharFrom(list.get(n) >= threshold ? NONMATCHING_CHARS : matchingChars, rand));
    }
    return builder.toString();
  }

  private static char randomCharFrom(String s, Random rand) {
    return s.charAt(rand.nextInt(s.length()));
  }

  /**
   * Provides samples on a random distribution derived from the web.
   *

    for (int n = 0; n < length; n++) {
      builder.append(
          randomCharFrom(list.get(n) >= threshold ? NONMATCHING_CHARS : matchingChars, rand));
    }
    return builder.toString();
  }

  private static char randomCharFrom(String s, Random rand) {
    return s.charAt(rand.nextInt(s.length()));
  }

  /**
   * Provides samples on a random distribution derived from the web.
   *