De acordo com a especificação dos Portlets 2.0 (JSR 286), a interface PortletSession permite o armazenamento de objetos nos escopos
APPLICATION_SCOPE e PORTLET_SCOPE.
APPLICATION_SCOPE e SERVER_SCOPE.
SERVER_SCOPE e PORTLET_SCOPE.
CLUSTER_SCOPE e APPLICATION_SCOPE.
CLUSTER_SCOPE e SERVER_SCOPE.