code: private static void validateInput(ColumnType columnType) throws ExecutionException {
          if (columnType == null) {
              String messagge = "The ColumnType can not be null.";
              LOGGER.error(messagge);
              throw new ExecutionException(messagge);
          }
      }
docs: This method validate the Input.
  
  @param columnType the columnType.
  @throws ExecutionException if a exception happens.