what happens if we deploy a portlet extending GenericPortlet class but not providing any render method for view mode?

Deployment will be successful. But when portlet added to a page and portlet server trying to render the portlet we get

Server Error:

03:30:58,211 ERROR [PortletServlet:96] javax.portlet.PortletException: doView method not implemented
javax.portlet.PortletException: doView method not implemented


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