In some code blocks (especially in symfony DI related) it's impossible to guess what class the object has, but it's possible to use single-line annotation before assignment:
$object = $this->get('doctrine') ->getRepository('MyBundleName:Object') ->findOneById($id); /* @var $object \My\Bundle\Name\Entity\Object */
with this netbeans will be able to auto-complete $object-> calls.
Please note that this annotation should be places after variable defintion as above!
You can also use shorter path:
/* @var $object Object */
if you have
use My\Bundle\Name\Entity\Object
defined in top of your file.