Preventing NPE in getExtSerializableCollection(). Also improved comment
for method.
Added debugging logging messages.
Changed to use fixed port numbers for RMI instead of port 0. This way
can lock down firewall to only allow access to specific ports. This is
important for when running in a cloud, such as AWS so that system can be
secured.
Improved comment.
Changed RMI ports to use CoreConfig so they are settable and to have
default values of 2099 and 3099.