The GSSAPIServerSubjectFactory is a factory responsible for returning the Subject that should be used for handing the
GSSAPI based authentication for a specific request.
The authentication handlers will not perform any caching of the returned Subject, the factory implementation can either
return a new Subject for each request or can cache them maybe based on the expiration time of tickets contained within the
Obtain the Subject to use for the specified host.
All virtual hosts on a server could use the same Subject or each virtual host could have a different Subject, the
implementation of the factory will make that decision. The factory implementation will also decide if there should be a
default fallback Subject or if a Subject should only be provided for recognised hosts.
hostName - - The host name used for this request.
The Subject to use for the specified host name or null if no match possible.