code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new IllegalArgumentException();
      }
  
      switch (field) {
      case POOL_INFO_STRING:
        return isSetPoolInfoString();
      case JOB_INPUT_SIZE:
        return isSetJobInputSize();
      }
      throw new IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise