title: JPA- How to avoid updating child entity to default values using merge
body: <p>I'm trying to save an entity which has one child entity already persisted.
  I'm using merge to save the entity. The non persisted entity is saved but the existing entity is updated with the default values overriding the values in DB. </p>
  
  <p>ClassRoom -Main Class:</p>
  
  <pre><code> @OneToMany(
       orphanRemoval = true,
       fetch = FetchType.EAGER
   )
   @JoinTable(...)
   @Cascade(CascadeType.ALL)
   private List&lt;Students&gt; students;
  </code></pre>
  
  <p>In Students class:</p>
  
  <pre><code>@OneToOne(
     orphanRemoval = true,
     fetch = FetchType.EAGER
  )
  @Cascade(org.hibernate.annotations.CascadeType.ALL)
  private Student student;
  </code></pre>
  
  <p>In Student class , there is a field which has default value. The existing value in the entity is getting updated with the default value.</p>
  
  <p>I'm trying to save the parent entity (ClassRoom) with merge.</p>
  
  <p>Is merge the right operator in this scenario or any suggestions to solve this problem?</p>