@Override
  public int execute() throws HiveException {
    try {
      Hive.get(false).reloadFunctions();
      return 0;
    } catch (Exception e) {
      context.getTask().setException(e);
      LOG.error("Failed to reload functions", e);
      return 1;
    }
  }
Operation process of reloading the functions.
ql/src/java/org/apache/hadoop/hive/ql/ddl/function/reload/ReloadFunctionsOperation.java