Erro Retorno List encadeada Json no Vraptor

public class Quiz extends DefaultEntity {

	private static final long serialVersionUID = 1L;

	@OneToMany(mappedBy = "quiz", fetch = FetchType.EAGER, cascade = { CascadeType.PERSIST, CascadeType.MERGE })
	private List<GroupQuestions> groupQuestions;
	
	public List<GroupQuestions> getGroupQuestions() {
		return groupQuestions;
	}

	public void setGroupQuestions(List<GroupQuestions> groupQuestions) {
		this.groupQuestions = groupQuestions;
	}

}

@Entity
@Table(name="Group_Questions")
public class GroupQuestions extends DefaultEntity {

	private static final long serialVersionUID = 1L;

	@Column(name="text")
	private String text;
	
	@Enumerated(EnumType.STRING)
	@Column(name = "formation")
	private FormationEnum formation;
	
	@OneToMany(mappedBy = "groupQuestions", fetch = FetchType.EAGER, cascade = { CascadeType.PERSIST, CascadeType.MERGE })
	private List<Question> question;

@Get
@Path(value = {"/", ""})
public void getQuestionnaires() {		
	result.use(json())
		  .withoutRoot()
		  .from(questionnaires.todosAtivos())
		  .include("groupQuestions")
                      .include("question")
                       .include("answers")
		  .serialize();
}

{
	"groupQuestions": [{
		"text": "Continuidade aos Estudos",
		"formation": "GRADUACAO_COMPLETA",
		"question": [{
			"text": "Está cursando MBA?",
			"componentType": "RADIO",
			"answers": [{
				"text": "sim"
			}, {
				"text": "nao"
			}, {
				"text": "talvez"
			}]
		}]
	}]
}