フリー問題

問題文

An application keeps four beans, one in each of the request, session, application and conversation scopes. Which of those beans have to be serializable?

選択肢

1. The application one has to be serializable, while the request, session and conversation ones are free of that requirement because the container recreates them
2. The request, session and conversation ones have to be serializable, while the application one is free of that requirement because it is created once for the whole server
3. The session and conversation ones have to be serializable, while the request and application ones are free of that requirement because their state is held in memory
4. The session, application and conversation ones have to be serializable, while the request one is free of that requirement because its context lasts for a single call of the client