In the activation protocol, incarnation numbers allow the activator to
discover an out-of-date call when a group reports it is inactive.
In the current implementation, the incarnation numbers are not used
properly. The activator should increment the incarnation number of a
group when the group is deemed inactive, and the incarnation number
also needs to be stored persistently. It is also may be required
that the group's incarnation number be added as a parameter to the
ActivationInstantiator.newInstance method and the
ActivationMonitor.activeObject method so that the group and activator
can weed out late calls for a previous group incarnation.
method