title: How to customize Jackson type information mechanism
body: <p>In Jackson, I am using annotation <strong>@JsonTypeInfo</strong> to include polymorphism support.</p>
  
  <p>If, I do not want to go with annotation based approach, I can use global default typing or override the type information handling module. </p>
  
  <p>I have tried global type information but it is emitting type information for all non final type.</p>
  
  <p>What I need , </p>
  
  <ol>
  <li>I want to include type information only for polymorphic type.</li>
  <li>I want to change default format of type info (to key-value pair)</li>
  </ol>
  
  <p>Is it possible to achieve above two points just by twitting global configuration?</p>
  
  <p>If not, what extension point should I used used to customize type-information module ? 
  I have read <strong>JacksonAnnotationIntrospector</strong> is the class which deals with type info.</p>
  
  <p>Should I customize it to achieve above mentioned two points?</p>
  
  <p>Help with Example will be well and good.</p>