Are autowired objects in spring-mvc threadsafe?

Question

Question 1) From my understanding spring creates singletons objects, So when I have a controller like below with a autowired service, will that affect threadsafety.

Question 2) If I declare a int type variable at class level and use it in controller or service, will it affect thread safety?

@Controller
public class LoginController {

    @Autowired
    public DaoService daoservice;

    @RequestMapping("/")
    public String getBookInfo() {
        Book book = daoservice.getBookbyId(1L);
        System.out.println(book.getTitle());
        return "welcome";
    }
}


@Service
public class DaoService {

    @Autowired
    public BookRepository BookRepo;

    public Book getBookbyId(Long Id) {
        Book book = BookRepo.findOne(Id);
        return book;
    }

}

Answer 1

Q.1 : Are Spring Beans Thread Safe?
Answer: No.
Spring don't give you thread safety for their bean. Spring provide different type of bean scope like (Prototype,Singleton etc). If Prototype then a new bean create each time it invoke where a singleton bean created for one time and shared in application context.

If you are thinking for HTTP request, then 2 or more request can come.Hence new instance of a bean is created in each request scope. So you can think they are thread safe in context of HTTP request but it's not truly thread safe by spring itself.Because several thread can share the bean within the same HTTP request context.

Q.2 : Are Class variable Thread Safe?
Answer: No
Quoted from here
All private member variables are shared. They might be final, but that only means that the references can't be changed. Any mutable state must be synchronized.