public class MyConfiguration extends DefaultConfigurationAction {

@Override
public void processAction(PortletConfig portletConfig,
ActionRequest actionRequest, ActionResponse actionResponse)
throws Exception {

super.processAction(portletConfig, actionRequest, actionResponse);
}

@Override
public String render(PortletConfig portletConfig,
RenderRequest renderRequest, RenderResponse renderResponse)
throws Exception {

return "/WEB-INF/jsp/configuration.jsp";

}

}

<configuration-action-class>com.liferay.portal.example.configuration.MyConfiguration</configuration-action-class>