public class UserService { @Inject private UserRepository userRepository; @Inject public UserService(UserRepository userRepository) { this.userRepository = userRepository; } @Inject public void setUserRepository(UserRepository userRepository) { this.userRepository = userRepository; } // ... } public class UserService { @Inject @Qualifier("mysql") private UserRepository userRepository; // ... } public class UserService { @Inject @Named("mysql") private UserRepository userRepository; // ... }