// $em is empty, all repositories are empty, data is inside DB


$q       = $em->createQuery('SELECT b FROM Foo\Bar b WHERE b.id=?1'); // Plays a query, that's OK
$q->setParameter(1, 1);
$result = $q->getSingleResult();


$entity = $em->find('Foo\Bar', 1);  // No query here, as the Entity is yet in the repo