code: public static String format(boolean[] b, final String sep) {
      return (b == null) ? "null" : (b.length == 0) ? "" : //
          formatTo(new StringBuilder(), b, ", ").toString();
    }
docs: Formats the boolean array b with ',' as separator.
  
  @param b the boolean array to be formatted
  @param sep separator between the single values of the array, e.g. ','
  @return a String representing the boolean array b