title: Ebean overridden save, update methods are not getting called through cascade save, update
body: <p>I have a base class:</p>
  
  <pre><code>import java.util.Date;
  
  import javax.persistence.Column;
  import javax.persistence.GeneratedValue;
  import javax.persistence.Id;
  import javax.persistence.MappedSuperclass;
  import javax.persistence.PrePersist;
  import javax.persistence.PreUpdate;
  import javax.persistence.Version;
  
  import play.db.ebean.Model;
  
  @MappedSuperclass
  public class TimeStampable extends Model {
  
      @Id
      @GeneratedValue
      public Long id;
  
      @Column(name = "created_at")
      public Date createdAt;
  
      @Column(name = "updated_at")
      public Date updatedAt;
  
      @Version
      public int version;
  
      @Override
      public void save() {
          if (this.id == null) {
              createdAt();
          } else {
              updatedAt();
          }
          super.save();
      }
  
      @Override
      public void update() {
          updatedAt();
          super.update();
      }
  
      @Override
      public void update(Object o) {
          updatedAt();
          super.update(o);
      }
  
      @PrePersist
      void createdAt() {
          this.createdAt = this.updatedAt = new Date();
      }
  
      @PreUpdate
      void updatedAt() {
          this.updatedAt = new Date();
      }
  }
  </code></pre>
  
  <p>And 2 models</p>
  
  <pre><code>public class Request extents TimeStampable {
       @OneToMany(cascade = CascadeType.ALL)
       public List&lt;Response&gt; responses = new ArrayList&lt;Response&gt;();
  }
  
  public class Response extents TimeStampable {
  }
  </code></pre>
  
  <p>when I try to save a Request object, I see that my DB has created_at updated_at fields correctly populated for the Request object but for the Response objects, those values are null. Other fields of the response objects have the expected values (that I had filled in).</p>
  
  <p>Here is how I am saving the request.</p>
  
  <pre><code>Request req = new Request();
  Response res = new Response();
  // code to populate response fields
  
  request.add(res);
  Ebean.save(req);
  </code></pre>
  
  <p>What am i missing here?</p>