@Inject
	private ObjectiveRepository objectiveRepository;

	@Inject
	private ActionRepository actionRepository;

.......


	public Action createAction(long participantId, TkModule module, long objectiveId, ActionModel actionModel) {

		Objective objective = objectiveRepository.findByParticipantIdAndModuleAndId(participantId, module, objectiveId);

		if (objective != null) {
			Action action = new Action();
			action.setName(actionModel.getName());
			action.setAmount(actionModel.getAmount());
			action.setDateStart(actionModel.getDateStart());
			if (actionModel.getDateEnd() != null) {
				action.setDateEnd(actionModel.getDateEnd());
			}
			action.setFrequencyFlag(actionModel.getFrequencyFlag());
			action.setDaysOfWeek(actionModel.getDaysOfWeek());
			action.setObjective(objective);

			objective.getActions().add(action);
			
			objectiveRepository.save(objective);
//здесь пока по умолчанию, но по сохранению objective action-объект сохраняется в БД, но id=0 так и остается в списке.
			//return action;
		} else {
			throw new ServiceException("The action with this ID does not exist.", "objective.id.bad");
		}
	}

@Entity
@Data
public class Objective implements Serializable {

	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "objective_id")
	private Long id;

.............................

	/**
	 * the actions of objective
	 */
    @OneToMany(mappedBy = "objective", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @Column(nullable = true)
    @JsonManagedReference
	private List<Action> actions;

}

@Entity
@Data
public class Action {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private long id;

......................

	/**
	 * objective of this action
	 */
	@ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
	@JoinColumn(name = "objective_id")
	@JsonBackReference
	private Objective objective;

}

objective.getActions().add(actionRepository.save(action));

	@Transactional(readOnly = false)
	save(Action action);

	@Transactional(readOnly = false)
	Action save(Action action);

org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist:  com.service.objective.domain.objective.Objective; nested exception is org.hibernate.PersistentO
bjectException:

@RepositoryDefinition(domainClass = Objective.class, idClass = Long.class)
@Transactional(readOnly = true)
public interface ObjectiveRepository {

	/**
	 * Saves the given objective.
	 * 
	 * @param objective the objective
	 */
	@Transactional(readOnly = false)
	void save(Objective objective);

	/**
	 * Delete the given objective.
	 * 
	 * @param objective the objective
	 */
	@Transactional(readOnly = false)
	void delete(Objective objective);

	/**
	 * finds any objective by id
	 * 
	 * @param id 
	 * @return the objective
	 */
	Objective findById(long id);

}

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL,orphanRemoval=true)
    @Column(nullable = true)
    @JsonManagedReference
	private List<Action> actions;

	@ManyToOne(fetch = FetchType.EAGER)
	@JoinColumn(name = "objective_id")
	@JsonBackReference
	private Objective objective;

	public void deleteAction(long participantId, TkModule module, long objectiveId, long actionId) {

		Action action = actionRepository.findAction(participantId, module, objectiveId, actionId);

		if (action != null) {
			Objective o = action.getObjective();
			o.getActions().remove(action);
			objectiveRepository.save(o);
//			actionRepository.delete(action);
		} else {
			throw new ServiceException("The action with this ID does not exist.", "action.id.bad");
		}
	}