XStream xstream = new XStream();
xstream.registerConverter(new HtmlEscapeStringConverter());
xstream.registerLocalConverter(One.class, "oneValue", new StringConverter());
// now make one field allow html characters
Bbb bbb = new Bbb();
bbb.setaValue("aaa-value");
bbb.setbValue("bbb-value");
Two twoObject = new Two();
twoObject.setOneValue("allow html: <img src=\"http://something.com/\" />");
twoObject.setTwoValue("interesting image: <img src=\"http://something.com/\" />");
twoObject.setBbb(bbb);