clean-arch.java

// domain
class User {}
class UserRequest {}
class ProjectCreator {}
class UserCreator {
  UserCreator(Supplier<OffsetDateTime> now, ProjectCreator projectCreator) {}
  User create(UserRequest r)
}

// service layer

// 1. varianta
class UserService1 {
  User createUser(UserRequest r) {
    User user = new UserCreator(OffsetDateTime::now, new ProjectCreator()).create(r);
    this.respository.save(user);
    return user.id;
  }
}

// 2. Varianta
class UserService2 {
  @Autowire
  private final UserCreator userCreator;

  User createUser(UserRequest r) {
    User user = this.userCreator.create(r);
    this.respository.save(user);
    return user.id;
  }
}