code: private static boolean isParameterSeparator(char c) {
          if (Character.isWhitespace(c)) {
              return true;
          }
          for (char separator : PARAMETER_SEPARATORS) {
              if (c == separator) {
                  return true;
              }
          }
          return false;
      }
docs: Determine whether a parameter name ends at the current position,
  that is, whether the given character qualifies as a separator.