@Override
    public Object postRead(Object o) {
      if (o == null) return o;
      Class<?> type = o.getClass();
      if (GenericUDFBridge.class == type)  {
        ((GenericUDFBridge)o).setUdfChecker(fnCheckerImpl);
      }
      // This won't usually be called otherwise.
      preRead(type);
      return o;
    }
A global hook that checks all subclasses of GenericUDF against the whitelist. It also injects
us into GenericUDFBridge-s, to check with the whitelist before instantiating a UDF.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/LlapDaemon.java