No converter found capable of converting from type to type #2 - spring-boot

Question

I know it's another similar question, but I can't answer it myself, that's why I'm writing to you for help.
I try to create my own #Query and returns a conversion error on two occasions. My guess is there is a problem with the service, but this is where my knowledge ends.
Here is my code:
Main entity
#Data
#Entity
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
private String name;
private String city;
private Date startDate;
private boolean stat;
public User() {
}
public User(String name, String city, Date startDate, boolean stat) {
this.name = name;
this.city = city;
this.startDate = startDate;
this.stat = stat;
}
}
2.Second model
public class UserName {
private String firstname;
public UserName() {
}
public UserName(String firstname) {
this.firstname = firstname;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
}
3.Third model
public class UserCount {
private String city;
private int count;
public UserCount() {
}
public UserCount(String city, int count) {
this.city = city;
this.count = count;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
}
Repository
#Repository
public interface UserRepository extends JpaRepository<User, Long> {
#Query("select p from User p") //1.it's work
List<User> getAll();
#Query("select u from User u where u.name like %?1") //2.it's work
List<User> findByFirstnameEndsWith(String firstname);
#Query("select u.name from User u ") //3. don't work
List<UserName> getNameUsers();
// this SQL working in database console H2
// SELECT city, count(*) FROM USERS WHERE stat = true GROUP BY city
#Query("select u.city, count (u) from User u where u.stat = true group by u.city") //3. don't work
List<UserCount> getOwnQuery();
}
Service
#Service
public class UserService {
#Autowired
private UserRepository repo;
public List<UserName> getN (){
return repo.getNameUsers();
}
public List<UserCount> getC(){
return repo.getOwnQuery();
}
}
Controller
#Controller
public class MyController {
#Autowired
private UserRepository repo;
#Autowired
private UserService repoService;
#GetMapping("/") //1.it's work
ResponseEntity<List<User>> getAllCity(Pageable page){
return ResponseEntity.ok(repo.getAll());
}
#GetMapping("/s") //2.it's work
ResponseEntity<List<User>> getAllUsers(Pageable page){
return ResponseEntity.ok(repo.findByFirstnameEndsWith("Seba"));
}
#GetMapping("/f") ///3.don't work
ResponseEntity<List<UserName> >getUsersName(Pageable page){
return ResponseEntity.ok(repoService.getN());
}
#GetMapping("/c") ///4.don't work
ResponseEntity<List<UserCount> >getUsersCount(Pageable page){
return ResponseEntity.ok(repoService.getC());
}
}
It also adds source code on GitHub
sorry i didn't add the error code

Answer 1

Use constructor with NEW keyword in #Query to get List<UserName>
#Query("select NEW com.sub.model.UserName(u.name) from User u ")
List<UserName> getNameUsers();
And do the same for List<UserCount>
#Query("select NEW com.sub.model.UserCount(u.city, count(u)) from User u where u.stat = true group by u.city")
List<UserCount> getOwnQuery();