code: public static Map<String, String[]> parameter2Map(final IRequestParameters _parameters)
      {
          final Map<String, String[]> ret = new HashMap<>();
          for (final String name : _parameters.getParameterNames()) {
              ret.put(name, ParameterUtil.parameter2Array(_parameters, name));
          }
          return ret;
      }
docs: Get an array for the StringValues.
  
  @param _parameters IRequestParameters
  @return always StringArray, if parameter does not exist an empty
  StringArray