xstream.alias("person", Person.class);
StringWriter buffer = new StringWriter();
// serialize
HierarchicalStreamWriter writer = new PrettyPrintWriter(buffer);
writer.startNode("people");
xstream.marshal(new Person("Postman", "Pat"), writer);
xstream.marshal(new Person("Bob", "Builder"), writer);
xstream.marshal(new Person("Tinky", "Winky"), writer);
writer.endNode();