<extension point="org.eclipse.ui.popupMenus">
  <objectContribution
      objectClass="org.eclipse.core.resources.IFile"
      nameFilter="*.wsdl"
      id="org.eclipse.wsdl.validate.wsdlaction">
     <action
        id="org.eclipse.wsdl.validate.ValidateWSDLActionDelegate"
        label="Validate WSDL File"
        class="org.eclipse.wsdl.validate.ValidateWSDLActionDelegate"
        enablesFor="1"/>
  </objectContribution>
</extension>

Example 2: Pop-up menu extension point.