title: spring-boot-starter-data-jpa @OneToMany does not insert new child when it's an update
body: <p>Parent:</p>
  
  <pre><code>import javax.persistence.CascadeType;
  import javax.persistence.Column;
  import javax.persistence.Embedded;
  import javax.persistence.Entity;
  import javax.persistence.GeneratedValue;
  import javax.persistence.GenerationType;
  import javax.persistence.Id;
  import javax.persistence.OneToMany;
  
  @Entity
  public class A {
  
  @Id
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  public Long id;
  
  @OneToMany(cascade = {CascadeType.ALL}, orphanRemoval = true)
  public List&lt;Child&gt; child = new LinkedList&lt;&gt;();
  
  }
  </code></pre>
  
  <p>Child:</p>
  
  <pre><code>@Entity
  public class Child {
  
  @Id
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  public Long child_id;
  
  }
  </code></pre>
  
  <p>Repository:</p>
  
  <pre><code>import org.springframework.data.repository.CrudRepository;
  @Transactional
  public interface ARepository extends CrudRepository&lt;A,Long&gt; {
  
  @Query("SELECT x FROM A x WHERE x.syncTimestamp IS NULL")
  List&lt;A&gt; findAs();
  }
  </code></pre>
  
  <p>Persisting :  Update  </p>
  
  <pre><code>public class SomeClass {
  
    @Autowired
    private ARepository repo;
  
    public void someMethod() {
  
      List&lt;A&gt; as = repo.findAs();
      A firstA = as.get(0);
      firstA.child.add(new Child());
      repo.save(firstA);
    }    
  
  }
  </code></pre>
  
  <p>When I insert a new A object, everything works fine, all the child insert well in the database. </p>
  
  <p>But when I load an A object from the database, add some child to the list and then update the object, this doesn't insert the new child. </p>
  
  <p>According to the documentation for CascadeType, ALL should insert them.</p>
  
  <p>Any idea how to fix this?</p>