The transaction is commited. That's not the problem.
From the java doc of the EntityManager.find() method:
If the entity instance is contained in the persistence context, it is returned from there.
It means that : the find won't fetch the object from the DB if it is already present in your entityManager.
To refresh the entity, simply call refresh(entity):
MyEntity myEntity = entityManger.find(MyEntity.class, Long.valueOf(entityId));
entityManger.refresh(myEntity);