@org.apache.thrift.annotation.Nullable
    public static _Fields findByThriftId(int fieldId) {
      switch(fieldId) {
        case 1: // START_ROW_OFFSET
          return START_ROW_OFFSET;
        case 2: // ROWS
          return ROWS;
        case 3: // COLUMNS
          return COLUMNS;
        case 4: // BINARY_COLUMNS
          return BINARY_COLUMNS;
        case 5: // COLUMN_COUNT
          return COLUMN_COUNT;
        default:
          return null;
      }
    }
Find the _Fields constant that matches fieldId, or null if its not found.
service-rpc/src/gen/thrift/gen-javabean/org/apache/hive/service/rpc/thrift/TRowSet.java