Dúvida saveOrUpdate hibernate

private Date creationDate;  
private Date lastUpdate;  
private String idUpdUser;

public abstract class BaseService<T extends BaseEntity> {
	protected Class<T> persistentClass;
	protected BaseServiceValidator baseServiceValidator;
	protected ExceptionFactory exceptionFactory;

	public BaseService(Class<T> persistentClass, String moduleName) {
		this.persistentClass = persistentClass;
		this.exceptionFactory = ExceptionFactory.getInstance(moduleName);
		this.baseServiceValidator = BaseServiceValidator
				.getInstance(moduleName);
	}

	public void validateBeforeSave(Collection<T> entities) {
		for (T entity : entities) {
			validateBeforeSave(entity);
		}
	}

	public void validateBeforeRemove(Collection<T> entities) {
		for (T entity : entities) {
			validateBeforeRemove(entity);
		}
	}

	public void save(T entity) {
		try {
			validateBeforeSave(entity);
			saveOrUpdate(entity);
		} catch (BusinessException e) {
			throw e;
		} catch (Throwable t) {
			throwSystemException(t);
		}
	}
//muitos outros métodos

<class name="SyncProduct" table="sync_prod" schema="public">
		<id name="id" column="cd_sync_prod">
			<generator class="sequence">
				<param name="sequence">sync_prod_cd_sync_prod_seq</param>
			</generator>
		</id>
		<many-to-one name="equipment" class="Equipment" lazy="false"
			fetch="join">
			<column name="cd_eqpmt" not-null="true" />
		</many-to-one>
		<many-to-one name="product"
			class="br.com.xxx.product.Product" lazy="false" fetch="join">
			<column name="cd_prod" not-null="true" />
		</many-to-one>
		<property name="creationDate">
			<column name="dt_creat" not-null="true" />
		</property>
		<property name="lastUpdate">
			<column name="dt_upd" not-null="true" />
		</property>
		<property name="idUpdUser">
			<column name="id_upd_user" not-null="true" />
		</property>
	</class>

CREATE TABLE sync_prod
(
  cd_sync_prod serial NOT NULL,
  cd_eqpmt integer NOT NULL,
  cd_prod integer NOT NULL,
  dt_creat timestamp(6) without time zone NOT NULL,
  dt_upd timestamp(6) without time zone NOT NULL,
  id_upd_user character varying(20) NOT NULL,
  CONSTRAINT pk_sync_prod PRIMARY KEY (cd_sync_prod),
  CONSTRAINT fk_sync_eqpmt FOREIGN KEY (cd_eqpmt)
      REFERENCES equipment (cd_eqpmt) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT fk_sync_prod FOREIGN KEY (cd_prod)
      REFERENCES product (cd_prod) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
)