This class is factory for creating new Connection objects.
The creation of Connections is performed dynamically by looking
up a protocol implementation class whose name is formed from the
platform name (read from a system property) and the protocol name
of the requested connection (extracted from the parameter string
supplied by the application programmer.)
The parameter string that describes the target should conform
to the URL format as described in RFC 2396.
This takes the general form:
{scheme}:[{target}][{params}]
where {scheme} is the name of a protocol such as
http}.
The {target} is normally some kind of network
address.
Any {params} are formed as a series of equates
of the form ";x=y".