@Controller
    public class A {
        @Autowired
        private OrderService orderService;
        @Autowired
        private UserRepository userRepository;

        @RequestMapping(value = "/createOrder", method = RequestMethod.POST)
        @ResponseBody
        public CreateOrderResponse createOrder(@RequestBody CreateOrderRequest request) {
            User user =  userRepository.findOne(request.getUserId());
            if(user == null){
                throw new SomeException(1, "User not found!");
            }
            orderService.createOrder(...);
        }
    }

 User user =  userRepository.findOne(request.getUserId());
    if(user == null){
        throw new SomeException(1, "User not found!");
    }

@Entity
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "first_name")
    private String firstName;
     
    ....
    + set/get

@Entity
public class CoffeMashine {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "type")
    private String type;

    GET/SET
    .....

    public void makeCoffee(some parameters){
        .......
    }