To provide its interactive functionality, the SampleForm portlet has its own action class, named DisplayAction. The name of the class is specified in the type subelement of the <portlet-action> element.

      <portlet-actions>
         <portlet-action name="display" default="true">
            <type>sample.form.DisplayAction</type>
         </portlet-action>
      </portlet-actions>
   </local-portlet> 
</portlets>