title: Sorting with hibernate single table inheritance strategy
body: <p>In my application I have three entities, BaseNotification as a parent and SmsNotification and EmailNotification as child entities which extend BaseNotification.</p>
  
  <p>I am using hibernate single table inheritance strategy so all attributes fit into one table.</p>
  
  <p>Lets say I have some common attributes on BaseNotification entity, and child entities have one specific attribute each (SmsNotification has mobileNumber and EmailNotification has email attribute).</p>
  
  <pre><code>public abstract class BaseNotification implements Serializable {
  
      private static final long serialVersionUID = 1L;
  
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      private Long id;
  
      @Column(name = "name")
      private String name;
  
      @Column(name = "description")
      private String description;
  ...
  }
  
  public abstract class EmailNotification extends BaseNotification implements Serializable {
  
      private static final long serialVersionUID = 1L;
  
      @Column(name = "email")
      private String email;
  ...
  }
  
  public abstract class SmsNotification extends BaseNotification implements Serializable {
  
      private static final long serialVersionUID = 1L;
  
      @Column(name = "mobileNumber")
      private String mobileNumber;
  ...
  }
  </code></pre>
  
  <p>Is there a way of fetching all notifications with all attributes while sorting on child attributes (for example by email) in one go with spring rest?</p>