public boolean isUdfAllowed(Class<?> clazz) {
    return FunctionRegistry.isBuiltInFuncClass(clazz) || allowedUdfClasses.containsKey(clazz);
  }
This class localizes and manages jars for the functions allowed inside LLAP.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/FunctionLocalizer.java