Question

I’m trying to fetch an entity in App Engine with Objectify v4 but it doesn’t work.

• My @Entity: Translation.class
• The @Id of the @Entity I want to fetch: 301L

My @Entity:

@Entity
public class Translation {
  @Id
  private Long id;
  private String text;

  public String getText() {
    return text;
  }

  public Long getId() {
    return id;
  }

  public void setText(String text) {
    this.text = text;
  }
}

The request that doesn’t word:

Translation translation =ObjectifyService.ofy().load().type(Translation.class).id(301L).get(); // translation is null

But if I do:

 Translation translation = ObjectifyService.ofy().load().type(Translation.class).first().get(); // translation is not null

Then:

System.out.println(translation.getId()); // translation id equal 301

So the fetch by id doesn’t seem to work.
Where is the problem?

Answer 1

Since your entity has a @Parent field, in order to get it by id, you need to execute:

Translation translation = ObjectifyService.ofy().load().type(Thing.class).parent(par).id(301).get();

For more information take a look at Objectify Basic Operations – Loading

Hope this helps!