I'm using JPA2 and Springboot2X. Trying to define a simple one-to-one relationship in User and Account tables. User is the parent while Account is the child. The relationship is from parent to child. Followed this.

User table has a column account_no to hold the account number which is the primary key of the Account table. So User holds the foreign key.

@Entity
public class Account extends AbstractEntity implements Serializable{

    // fields like account#, balance etc goes here..

    @OneToOne (fetch = FetchType.LAZY)
    private User user;

}

@Entity
public class User extends AbstractEntity implements Serializable{

    // Other fields related to user entity go here ..

    @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "account_no", referencedColumnName = "account_number")
    private Account account;
}

Saving is working properly. But when I fetch a user ( User user = userRp.findByUserID(userid);), I get data from both tables. My question is when I define fetch = FetchType.LAZY why the account table data is fetching? I only want the user data to be in the output as when I run the select query in the User table.

Output :

    {
    "id": 1,
    "userID": "xxxxx",
    "firstName": "Dsd",
    "llastName": "cccc",
    "email": "danqsaa@brown",
    "creation_date": "2021-12-19 19:41",
    "modified_date": "2021-12-19 19:41",
    "account": {
        "id": 2,           
        "accountNo": 6848982326,
        "balance": 4000.0,
        "creationUser": "xxx",
        "creation_date": "2021-12-19 19:41",
        "modified_date": "2021-12-19 19:41",
        "transactions": []
    }
}

DB output

Added below RestController, Service, and Repo details.

@RestController
public class UserController {

    @GetMapping("/users/{userID}")
        public ResponseEntity<Object> getUser(@PathVariable("userID") String userID){
                   return new ResponseEntity<>(userServiceImpl.getUserByID(userID), HttpStatus.OK)); 
        }
}

@Service
public class UserService {

 // injected user repo
public User getUserByID(String userID){
        return  userRepo.findByUserID(userID);      
    }
}

public interface UsersRepository extends CrudRepository<User, String> {
     User findByUserID(String userID);
}