**My Controller Class**

 Class's are in four different packages

 com.booking.controller
 com.booking.model
 com.booking.repository
 com.service

 Here i have problem ,simply it can't see service class.

@Controller
@RequestMapping(path = "/user")
public class UserController{
@Autowired
private UserRepository userRepository;

@GetMapping(path = "/add")
public @ResponseBody String addNewUser(@RequestParam String name,
@RequestParam String username,
        @RequestParam String email, @RequestParam String password) {

    User n = new User();
    n.setName(name);
    n.setUsername(username);
    n.setEmail(email);
    n.setPassword(password);
    userRepository.save(n);
    return "Saved";
}

@GetMapping(path = "/all")
public @ResponseBody Iterable<User> getAllUsers() {
    return userRepository.findAll();
}

@RequestMapping("/{Id}")
public User getUser(@PathVariable Long id) {
    return userRepository.getUser(id);
/*Here you can see problem*/
}

}

**My User Class**

@Entity
public class User implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@Column
private String name;

@Column
private String username;

@Column
private String email;

@Column
private String password;

public User() {

}

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

}

**My Repository Class--

public interface UserRepository extends CrudRepository<User, Long> {
public List<User> findByUsername(String username);


}

**My Service Class**

@Service
public class UserService {
@Autowired
private UserRepository userRepository;

public List<User> getAllUsers(String username) {
    List<User> users = new ArrayList<>();
    userRepository.findByUsername(username).forEach(users::add);
    return users;
}

public User getUser(Long id) {
    return userRepository.findOne(id);
}

public void addUser(User user) {
    userRepository.save(user);
}

public void updateUser(Long id, User user) {
    userRepository.save(user);
}

public void deleteUser(Long id) {
    userRepository.delete(id);
}

}