Container container = new Container(); container.register(UserService.class, new UserServiceImpl()); container.register(UserRepository.class, new UserRepositoryImpl()); UserService userService = container.resolve(UserService.class); String result = userService.createUser("John"); System.out.println(result); Container container = new Container(); container.register(UserService.class, new UserServiceImpl()); container.register(UserRepository.class, new UserRepositoryImpl());