title: @Loader with @NamedNativeQuery NullPointerException
body: <p>I have 2 entity classes:</p>
  
  <pre><code>@Entity
  public class Product {
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      private int id;
      private String title;
  
      private String code;
      private long price;
  
      @OneToMany(mappedBy = "product", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
      @Loader(namedQuery = "productFields")
      private List&lt;ProductOwnerFields&gt; fields = new ArrayList&lt;&gt;();
  
      @OneToMany(mappedBy = "product", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
      private Set&lt;ProductPhoto&gt; photos = new HashSet&lt;&gt;();
  
      //getters and setters
  }
  
  @Entity
  @NamedNativeQueries({@NamedNativeQuery(
          name = "productFields",
          resultClass = ProductOwnerFields.class,
          query = "select p.* " +
                  "from productownerfields p " +
                  "   left outer join templatefields t " +
                  "       on p.templateField_id = t.id " +
                  "where p.product_id = ? " +
                  "order by t.order_field desc"
  )})
  public class ProductOwnerFields {
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      private int id;
  
      @ManyToOne(fetch = FetchType.EAGER)
      @JoinColumn(name = "product_id")
      private Product product;
  
      private String customValue;
  
      @OneToOne(fetch = FetchType.EAGER)
      @JoinColumn(name = "templateField_id")
      private TemplateFields templateFields;
  
      //getters and setters
  }
  </code></pre>
  
  <p>and DAO:</p>
  
  <pre><code>@Repository
  public class IProductDao implements ProductDao {
  
      @PersistenceContext
      private EntityManager entityManager;
  
      @Override
      public Product find(int id) {
          return entityManager.find(Product.class, id);
      }
  }
  </code></pre>
  
  <p>When I try to get product by find method I get exception for field calls "fields" of Product class:
  <em>unable to evaluate the expression Method threw 'java.lang.NullPointerException' exception.</em></p>
  
  <p>In a trace is named query is run:</p>
  
  <blockquote>
    <p><strong>TRACE</strong> o.h.type.descriptor.sql.BasicBinder - binding parameter [1] as
    [INTEGER] - [88] <strong>DEBUG</strong> org.hibernate.loader.Loader - Result set row: 0 <strong>TRACE</strong> o.h.t.descriptor.sql.BasicExtractor - extracted value ([id] :
    [INTEGER]) - [361]  <strong>DEBUG</strong> org.hibernate.loader.Loader - Result row:
    EntityKey[com.inetshop.core.entities.ProductOwnerFields#361]</p>
  </blockquote>
  
  <p>How can I fix this wrong? Set of ProductPhoto load is ok.</p>
  
  <p>Thank for your help!</p>