Updated PeopleController

PeopleController.java

@RestController
@RequestMapping("/api/people")
public class PeopleController {
    ...

    @PatchMapping("{id}")
    public ResponseEntity<Void> updatePerson(@PathVariable("id") long id,
                                             @Valid @RequestBody PersonUpdateDto personUpdateDto) {
        Optional<Person> personOptional = peopleRepository.getById(id);
        if (!personOptional.isPresent()) {
            return ResponseEntity.notFound().build();
        }

        Person person = personOptional.get();
        if (personUpdateDto.getFirstName().isPresent()) {
            person.setFirstName(personUpdateDto.getFirstName().get());
        }
        if (personUpdateDto.getLastName().isPresent()) {
            person.setLastName(personUpdateDto.getLastName().get());
        }
        if (personUpdateDto.getBirthday().isPresent()) {
            person.setBirthday(personUpdateDto.getBirthday().get());
        }
        if (personUpdateDto.getBio().isPresent()) {
            person.setBio(personUpdateDto.getBio().get());
        }
        if (personUpdateDto.getImageUrl().isPresent()) {
            person.setImageUrl(personUpdateDto.getImageUrl().get());
        }

        peopleRepository.save(person);

        return ResponseEntity.noContent().build();
    }
}