title: Doctrine 2 "Class does not exist" on persist
body: <p>So I have these two classes with OneToMany and ManyToOne relationships between them:</p>
  
  <pre>
  namespace RM\Entity;
  
  use Doctrine\Common\Collections\ArrayCollection;
  
  /**
   * @Table(name="users")
   * @Entity
   * @author Csabi
   */
  class User {
  
      /**
       * @Id
       * @Column(name="id", type="integer", nullable=false)
       * @GeneratedValue(strategy="IDENTITY")
       * @OneToMany(targetEntity="JobListing", mappedBy="ownerId", orphanRemoval=true)
       */
      private $id;
  
      /**
       * @var string $displayname
       * @Column(type="string", nullable=false)
       */
      private $displayname;
  }
  </pre>
  
  <p>and</p>
  
  <pre>
  namespace RM\Entity;
  
  use Doctrine\Common\Collections\ArrayCollection;
  
  /**
   * @Table(name="job_listings")
   * @Entity(repositoryClass="RM\Entity\Repository\JobListingRepository")
   * @author Csabi
   */
  class JobListing {
  
      /**
       * @var integer $id 
       * @Column(name="id", type="integer", nullable=false)
       * @Id
       * @GeneratedValue(strategy="IDENTITY")
       */
      private $id;
  
      /**
       * @var User
       * @ManyToOne(targetEntity="User",cascade={"persist"})
       * @JoinColumns({
       *  @JoinColumn(name="ownerId", referencedColumnName="id", nullable=false)
       * })
       */
      private $ownerId;
  </pre>
  
  <p>However, when saving a JobListing, on persist it throws the following error:</p>
  
  <pre>
  Application error
  Exception information:
  
  Message: Class does not exist
  Stack trace:
  
  #0 library\Doctrine\ORM\Mapping\ClassMetadata.php(67): ReflectionClass->__construct(false)
  #1 library\Doctrine\ORM\Mapping\ClassMetadataFactory.php(350): Doctrine\ORM\Mapping\ClassMetadata->__construct(false)
  #2 library\Doctrine\ORM\Mapping\ClassMetadataFactory.php(260): Doctrine\ORM\Mapping\ClassMetadataFactory->newClassMetadataInstance(false)
  #3 library\Doctrine\ORM\Mapping\ClassMetadataFactory.php(169): Doctrine\ORM\Mapping\ClassMetadataFactory->loadMetadata(false)
  #4 library\Doctrine\ORM\EntityManager.php(247): Doctrine\ORM\Mapping\ClassMetadataFactory->getMetadataFor(false)
  #5 library\Doctrine\ORM\UnitOfWork.php(1222): Doctrine\ORM\EntityManager->getClassMetadata(false)
  #6 library\Doctrine\ORM\UnitOfWork.php(1678): Doctrine\ORM\UnitOfWork->doPersist(1, Array)
  #7 library\Doctrine\ORM\UnitOfWork.php(1252): Doctrine\ORM\UnitOfWork->cascadePersist(Object(RM\Entity\JobListing), Array)
  #8 library\Doctrine\ORM\UnitOfWork.php(1201): Doctrine\ORM\UnitOfWork->doPersist(Object(RM\Entity\JobListing), Array)
  #9 library\Doctrine\ORM\EntityManager.php(454): Doctrine\ORM\UnitOfWork->persist(Object(RM\Entity\JobListing))
  #10 library\RM\Entity\JobListingService.php(54): Doctrine\ORM\EntityManager->persist(Object(RM\Entity\JobListing))
  #11 application\controllers\JobListingController.php(28): RM\Entity\JobListingService->saveJobListing(Object(RM\Entity\JobListing))
  #12 library\Zend\Controller\Action.php(516): JobListingController->addAction()
  </pre>
  
  <p>What am I missing here?</p>