code: public static boolean isIdStrict(char[] chars, int offset, int len) {
          if (len == 0) {
              return false;
          }
          int end = offset + len;
          if (!isIdStartStrict(chars[offset++])) {
              return false;
          }
          while (offset < end) {
              if (!isIdCharStrict(chars[offset++])) {
                  return false;
              }
          }
          return true;
      }
docs: Returns true if the string represented by the specified character array does not
  Uses the strict definition described in the Rison specification, appropriate for encoding.