Symfony 2.8 Doctrine fetch/display data trouble - php

Question

Following the Symfony 2.8 book examples for the most part, as a total beginner I'm having trouble fetching data from the database with a ManyToOne relationship. I have a database table categories and one deploys.
deploys has a category_id which refers to categories.id. So one category can have many deploys. The database has data, when I custom query in pma I get results.
My Question:
After executing my controller code I get a Collection (see image), but not filled with deploy elements as it seems. What am I doing wrong? How can I display the deploy elements with a certain category_id
In my Controller I do:
$category = $this->getDoctrine()->getRepository('AppBundle:Category')->find(1);
$deploys = $category->getDeploys();
dump($deploys);
die();
This will display:
I have a Deploy Entity: (part of it, it has been generated by app/console)
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
* #ORM\Table(name="deploys")
*/
class Deploy {
/**
* #ORM\Column(type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\ManyToOne(targetEntity="Category", inversedBy="deploys")
* #ORM\JoinColumn(name="category_id", referencedColumnName="id")
*/
private $category;
// etc
And a Category Entity:
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #ORM\Entity
* #ORM\Table(name="categories")
*/
class Category {
/**
* #ORM\Column(type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="string", length=255)
*/
private $name;
/**
* #ORM\Column(type="integer", length=10)
*/
private $weight;
/**
* #ORM\OneToMany(targetEntity="Deploy", mappedBy="category")
*/
private $deploys;
/**
* Constructor
*/
public function __construct() {
$this->deploys = new ArrayCollection();
}
// etc

Answer 1

This is lazy loading feature. They will be loaded form DB once you'll try to access them.
Try to simply access some elements of this collection (e.g. iterate over $deploys) and you will see it will work just fine.
Note that on your screen there is attribute initialized: false. That means that this collection was not accessed yet, so Doctrine didn't have to load it.