em.getTransaction().begin();
Class[] classes = { Game.class, IndoorGame.class, Scrabble.class,
Chess.class };
for (Class cls : classes) {
for (int i = 1; i <= 4; i++) {
Game p = (Game) cls.newInstance();
p.setName(cls.getSimpleName() + "-" + i);
em.persist(p);
}
}
em.getTransaction().commit();
}