code: @SuppressWarnings("unchecked")
      public List<String> getParamList(String paramName) {
          Object paramValue = getParam(paramName);
          if (paramValue == null) {
              return null;
          }
          if (!(paramValue instanceof List)) {
              throw new IllegalArgumentException("Parameter '" + paramName + "' must be a list: " + paramValue);
          }
          return (List<String>)paramValue;
      }
docs: Get the value of the given parameter name belonging to this service as a LIst of
  Strings. If no such parameter name is known, null is returned. If the parameter is
  defined but is not a list, an IllegalArgumentException is thrown.
  
  @param paramName     Name of parameter to get value of.
  @return              Parameter value as a List of Strings or null if unknown.