Spring @Transaction method call by the method within the same class, does not work?

Question

I am new to Spring Transaction. Something that I found really odd, probably I did understand this properly.

I wanted to have a transactional around method level and

Answer 1

With Spring 4 it's possible to Self autowired

@Service
@Transactional
public class UserServiceImpl implements UserService{
    @Autowired
    private  UserRepository repository;

    @Autowired
    private UserService userService;

    @Override
    public void update(int id){
       repository.findOne(id).setName("ffffd");
    }

    @Override
    public void save(Users user) {
        repository.save(user);
        userService.update(1);
    }
}

Answer 2

Starting from Java 8 there's another possibility, which I prefer for the reasons given below:

@Service
public class UserService {

    @Autowired
    private TransactionHandler transactionHandler;

    public boolean addUsers(List<User> users) {
        for (User user : users) {
            transactionHandler.runInTransaction(() -> addUser(user.getUsername, user.getPassword));
        }
    }

    private boolean addUser(String username, String password) {
        // TODO call userRepository
    }
}

@Service
public class TransactionHandler {

    @Transactional(propagation = Propagation.REQUIRED)
    public <T> T runInTransaction(Supplier<T> supplier) {
        return supplier.get();
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public <T> T runInNewTransaction(Supplier<T> supplier) {
        return supplier.get();
    }
}

This approach has the following advantages:

1. It may be applied to private methods. So you don't have to break encapsulation by making a method public just to satisfy Spring limitations.

2. Same method may be called within different transaction propagation and it is up to the caller to choose the suitable one. Compare these 2 lines:

   transactionHandler.runInTransaction(() -> userService.addUser(user.getUserName, user.getPassword)); transactionHandler.runInNewTransaction(() -> userService.addUser(user.getUserName, user.getPassword));

3. It is explicit, thus more readable.