title: Serializing JPA entities to JSON using Jackson
body: <p>Question regarding combination of Jackson/JPA</p>
  
  <ol>
  <li><p>If there are about 20 entities in current application and I have add Jackson dependency in POM, does it mean all entities are by default ready to convert to <code>JSON</code> object? I saw a sample project seems only class annotated as <code>@JsonIgnored</code> is skipped by <code>JSON</code>. If so, then how can this happen, what is behind such mechanism? how <code>JACKSON</code> handle those entities which don't have any Jackson annotation, by default ignored or not? I've been looking for resources online but not much luck. </p></li>
  <li><p>If only one of the 20 entities need to be mapped to JSON object, does it mean I have to add @JsonIgnore to all other 19 entities? If not, how <code>Jackson</code> differentiate with entity to work on?</p></li>
  </ol>
  
  <p>Thanks.</p>