Question for using wrapper class at POJO

Sorry, I don't know where is a suitable place to discuss the question, so I just open an issue here to ask my question.

I have a question about the 8th point of [OOP rules](https://github.com/alibaba/Alibaba-Java-Coding-Guidelines#oop-rules).
> 8. [Mandatory] Rules for using primitive data types and wrapper classes:
  1) Members of a POJO class must be wrapper classes.
  2) The return value and arguments of a RPC method must be wrapper classes.
  3) [Recommended] Local variables should be primitive data types.

Based on this rule, it will only allow us to use the primitive type in local variables. Then, we need to use wrapper classes in all other places.

The thing is that most of the suggestions I saw at the Internet is we should avoid wrapper classes as much as possible.
The reasons are
- performance
- memory footprint

So could anybody explain the reason behind this rule? Thanks. 🙏

Commencez par les règles OOP liées, en particulier la règle 8 et ses indications sur les types primitifs et wrapper. Une explication ou une clarification de la règle approuvée par un maintainer constituerait un résultat utile, mais l’issue ne mentionne aucun fichier de documentation ni aucun test à mettre à jour.

Rédigé par le modèle d'indexation à partir du texte de l'issue.