An instance of Configuration allows the application
to specify properties and mapping documents to be used when
creating a SessionFactory. Usually an application will create
a single Configuration, build a single instance of
SessionFactory and then instantiate Sessions in
threads servicing client requests. The Configuration is meant
only as an initialization-time object. SessionFactorys are
immutable and do not retain any association back to the
Configuration.
A new Configuration will use the properties specified in
hibernate.properties by default.
A new Configuration will use the properties specified in hibernate.properties by default.