Class relationship by collections in JPA2

Question

In a bean that has a Onetomany connection, with others, through a Hashmap that annotations should be used?.

  @Entity
  class Rodada{
      public HashMap<Pergunta,Resposta> perguntas;

Answer 1

This relationship would be better structured within a wrapper class for these two entities:

@Entity
public class Questao {

   @Id
   private int id;
   @OneToOne
   private Pergunta pergunta;
   @OneToOne
   private Resposta resposta;

   // getter, setter, hashCode, equals

}

So in your class of rounds:

@Entity
public class Rodada {
  //Id omitido
  @OneToMany
  @JoinColumn(name = "rodada_id")
  private Set<Questao> questoes;

  // getter, setter, hashCode, equals  

}

If you still want to keep it the way it is, follow an example taken from Soen that can help you:

@ElementCollection
@CollectionTable(name="<name_of_join_table>")
@MapKeyColumn(name="<name_of_map_key_in_table>")
Map<String, Person> personMap;