package com.thoughtworks.xstream;
public class Cd {
	private String id;

	private Cd bonusCd;

	Cd(String id, Cd bonusCd) {
		this.id = id;
		this.bonusCd = bonusCd;
	}

	Cd(String id) {
		this.id = id;
	}

	public String getId() {
		return id;
	}

	public Cd getBonusCd() {
		return bonusCd;
	}
}

Cd bj = new Cd("basement_jaxx_singles");
Cd mr = new Cd("maria rita");
		
List<Cd> order = new ArrayList<>();
order.add(mr);
// adds the same cd twice (two references to the same object)
order.add(bj);
order.add(bj);

// adds itself (cycle)
order.add(order);

XStream xstream = new XStream();
xstream.alias("cd", Cd.class);
System.out.println(xstream.toXML(order));