configuration.addHostKey( "demo", "demo");
PortForwarding pf = new PortForwarding( "demo", "demo", 11, 22, "demo", PortForwardingType.SSH );
configuration.addPortForwardingToServer( "demo", pf );
XStream xstream = new XStream( new StaxDriver() );
xstream.alias( "root", DefaultShellConfiguration.class);
xstream.alias( "server-info", ServerInfo.class);
xstream.alias( "port-forwarding", PortForwarding.class );
xstream.alias( "host-key", HostKey.class );