child2.setChildren(grandChildren2);
PersistenceManager pm = pmf.getPersistenceManager();
FetchPlan fp = pm.getFetchPlan();
fp.clearGroups();
fp.addGroup("detailChildren3").removeGroup("default");
pm.currentTransaction().begin();
logger.log(BasicLevel.DEBUG, "make persistent the person " + grandParent.toString());
pm.makePersistent(grandParent);
pm.currentTransaction().commit();
logger.log(BasicLevel.DEBUG, "FG: " + fp.getGroups());