The NoRouteToHostException may be thrown when attempting to connect to a
remote machine and because of network fault or firewall, no route can be
established.
The abstract superclass of all classes that implement streaming sockets.
Streaming sockets are wrapped by two classes, ServerSocket and Socket at the
server and client end of a connection respectively.
SocketPermissionCollection is a class which holds a collection of
SocketPermission objects and can answer a boolean indicating whether or not a
specific permissions is implied by a SocketPermissionCollection.