This mapping does not make much sense. You can’t map festivalActions this way because there is no way to persist the state properly through such a mapping. Also festival in AreaDto should be mapped by the area in FestivalDto. Try the following instead:

@Entity
@Table(name = "AREA")
@EntityListeners(AuditingEntityListener.class)
public class AreaDto {

    @Id
    @Column(name = "AREA_ROWID")
    private String areaRowId;

    @OneToMany(cascade = CascadeType.DETACH, mappedBy = "area")
    private Collection<FestivalDto> festival;


    @OneToMany(cascade = CascadeType.DETACH, mappedBy = "area")
    private Collection<ActionDto> actions;

    public Collection<ActionDto> getFestivalActions() {
        return festival.stream().flatMap(f -> f.actions.stream()).collect(Collectors.toList());
    }


}

@Entity
@EntityListeners(AuditingEntityListener.class)
@Table(name = "FESTIVAL")
public class FestivalDto {

    @Id
    @Column(name = "FESTIVAL_ROWID")
    @GeneratedValue(generator = "FESTIVAL_ROWID_SEQ")
    private Long festivalRowId;

    
    @ManyToOne(cascade = CascadeType.DETACH, fetch = FetchType.LAZY, optional = true)
    @JoinColumn(name = "AREA_ROWID")
    private AreaDto area;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "festival")
    private Collection<ActionDto> actions = Lists.newArrayList();

}

@Entity
@EntityListeners(AuditingEntityListener.class)
@Table(name = "ACTION")
public class ActionDto implements Serializable {

...

    @Id
    @Column(name = "ACTION_ID")
    @GeneratedValue(generator = "ACTION_ID_SEQ")
    private Long actionId;

    @Audited(targetAuditMode = RelationTargetAuditMode.NOT_AUDITED)
    @ManyToOne(cascade = DETACH, fetch = FetchType.LAZY)
    @JoinColumn(name = "FESTIVAL_ROWID")
    private FestivalDto festival;

    @Audited(targetAuditMode = RelationTargetAuditMode.NOT_AUDITED)
    @ManyToOne(cascade = DETACH, fetch = FetchType.LAZY)
    @JoinColumn(name = "AREA_ROWID")
    private AreaDto area;


}