PortletException
The portal wants to ensure that portlets never
become stuck in an unusable state. To make sure
this happens, they want the ability to clear the
session if they repetedly catch exception from
container invocations
By implementing this services and registering
and administrative request handler, the portal
can invoke the doAdmin method of the container
and then receive the request through the handler
executing within the portlet environment (as
opposed to the portal environment)