4.3. オブジェクトのロード

cat = em.find(Cat.class, catId);

// You may need to wrap the primitive identifiers
long catId = 1234;
em.find( Cat.class, new Long(catId) );

child = new Child();
child.SetName("Henry");
Parent parent = em.getReference(Parent.class, parentId); //no query to the DB
child.setParent(parent);
em.persist(child);

em.persist(cat);
em.flush(); // force the SQL insert and triggers to run
em.refresh(cat); //re-read the state (after the trigger executes)