ServiceContainer.createContainer can return a container that is being shut
down.
The following sequence of events can occur:

1. In arbitrary order, from two different threads:
ServiceContainer.createContainer()
serviceContainer.stop()
(with the assumption that the porperties used to create the new container match
the one that is being stopped)
2.
createContainer: container = containers.get(properties)
close: dispatcher.stop()
close: containers.remove(this.properties)
createContainer: return container

That will cause a shut down container to be returned. The practical result for
my case is that GRAM will think that it started the notification listener, but
the client will never get any notifications.

One solution may be to consistently synchronize on the same object when using
the container map. Currently createContainer(), being static, synchronizes on
ServiceContainer.class, while stop and close syhchronize on the specific
container instance.