title: hibernate - how to save parent with detached child
body: <p>I am sending an object from UI. This object is going to be created with a reference to an existing child. </p>
  
  <p>This is simple illustration for this relation.</p>
  
  <pre><code>class ParentEntity {
      @Id
      Long id;
  
      @ManyToOne(fetch = FetchType.LAZY)
      private ChildEntity child;
  }
  
  class ChildEntity {
      @Id
      Long id;
  }
  
  
  
  ChildEntity child = new ChildEntity();
  child.setId(1);
  //parentEntity is created based on data sent from UI
  parentEntity.setChild(child);
  </code></pre>
  
  <p>When I save this object, Hibernate gives me " org.hibernate.TransientPropertyValueException: object references an unsaved transient instance ".</p>
  
  <p>I don't have to save a child as I do not change child at all. Just need to save child's id in parent's table.</p>
  
  <p>I've tried to use few CascadeType, but none of them worked.</p>