code: private boolean isWatermarkExists() {
      if (!Strings.isNullOrEmpty(this.state.getProp(ConfigurationKeys.EXTRACT_DELTA_FIELDS_KEY)) && !Strings
          .isNullOrEmpty(this.state.getProp(ConfigurationKeys.SOURCE_QUERYBASED_WATERMARK_TYPE))) {
        return true;
      }
      return false;
    }
docs: true if water mark columns and water mark type provided
  
  @return true if water mark exists