@org.apache.thrift.annotation.Nullable
    public static _Fields findByThriftId(int fieldId) {
      switch(fieldId) {
        case 1: // ID
          return ID;
        case 2: // STATE
          return STATE;
        case 3: // USER
          return USER;
        case 4: // HOSTNAME
          return HOSTNAME;
        case 5: // AGENT_INFO
          return AGENT_INFO;
        case 6: // HEARTBEAT_COUNT
          return HEARTBEAT_COUNT;
        case 7: // META_INFO
          return META_INFO;
        case 8: // STARTED_TIME
          return STARTED_TIME;
        case 9: // LAST_HEARTBEAT_TIME
          return LAST_HEARTBEAT_TIME;
        default:
          return null;
      }
    }
Find the _Fields constant that matches fieldId, or null if its not found.
standalone-metastore/metastore-common/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/metastore/api/TxnInfo.java