title: SQL Statement to Spring Data - PersistentEntity must not be null
body: <p>I´m doing a Web-Application with a Spring Boot Backend and an AngularJS frontend.<br>
  Database is MySQL.<br>
  I try do get the Top 5 Items out of my database. I´m doing this through the<br>
  @Query Annotation. I tried my SQL Statement directly onto the DB and i get the expected values.<br>
  SQL Statement:  </p>
  
  <pre><code> select item 
      from work_item   
      group by item  
      order by count(*) desc   
      limit 3  
  </code></pre>
  
  <p>@Query:  </p>
  
  <pre><code>@Query(value="SELECT WORK_ITEM_ITEM FROM WORK_ITEM GROUP BY WORK_ITEM_ITEM ORDER BY COUNT( *) DESC LIMIT 5", nativeQuery = true)  
  List&lt; String &gt; find5MostUsedItems();
  </code></pre>
  
  <p>When i try to access the related URL i´m getting the following error:  </p>
  
  <pre><code>java.lang.IllegalArgumentException: PersistentEntity must not be null!
  </code></pre>
  
  <p>Would be glad if someone could push me into the right direction.<br>
  In case you need more information, plz ask. (My first question :) )</p>
  
  <p>Edit: my Entity:</p>
  
  <pre><code>@Entity
  public class WorkItem {
  
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      @Column(name = "workItem_ID")
      private long id;
      @Column(name = "workItem_date")
      private LocalDate date;
      @Column(name = "workItem_mitarbeiterNummer")
      private int mitarbeiterNummer;
      @Column(name = "workItem_startTime")
      private LocalTime startTime;
      @Column(name = "workItem_endTime")
      private LocalTime endTime;
      @Column(name = "workItem_workDuration")
      private int workDuration;
      @Column(name = "workItem_item")
      private String item;
      @Column(name = "workItem_itemDescription")
      private String itemDescription;
  </code></pre>
  
  <p>Greetings!</p>