Update

Service

public DepartmentDTO update(UUID id, DepartmentDTO dto) {
    Department entity = departmentRepository.getById(id);
    entity.setName(dto.getName());
    departmentRepository.save(entity);
    return new DepartmentDTO(entity);
}

Controller

@PutMapping(value = "/{id}")
public ResponseEntity<DepartmentDTO> update(@PathVariable UUID id, @RequestBody DepartmentDTO dto) {
    dto = departmentService.update(id, dto);
    return ResponseEntity.ok().body(dto);
}