@org.apache.thrift.annotation.Nullable
    public static _Fields findByThriftId(int fieldId) {
      switch(fieldId) {
        case 1: // STAGE_ID
          return STAGE_ID;
        case 2: // STAGE_TYPE
          return STAGE_TYPE;
        case 3: // STAGE_ATTRIBUTES
          return STAGE_ATTRIBUTES;
        case 4: // STAGE_COUNTERS
          return STAGE_COUNTERS;
        case 5: // TASK_LIST
          return TASK_LIST;
        case 6: // DONE
          return DONE;
        case 7: // STARTED
          return STARTED;
        default:
          return null;
      }
    }
Find the _Fields constant that matches fieldId, or null if its not found.
ql/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/ql/plan/api/Stage.java