startTx(em);
//create and persist multiple entity1 instances
for (int i = 0; i < instNum; i++) {
Entity1 ent = new Entity1(i, "string" + i, i + 2);
Entity2 ent2 = new Entity2(i * 2, "ent2" + i, i);
ent.setEntity2Field(ent2);
em.persist(ent);
}
endTx(em);