Suppose you have two classes A and B like this which are both declared with Annotations.configureAliases(): public abstract class A { @XStreamAlias("test") @XStreamAsAttribute private String bug; } @XStreamAlias("concrete") public class B extends A { @XStreamAlias("firstName") @XStreamAsAttribute private String name; } Then XStream persists an instance of B like this: <concrete firstName="michael" test="whatever"/> Then XStream will not read the attribute 'test' from the XML document into the class since it expects the attribute name to be 'bug'. Basically the @XStreamAlias annotation is ignored in (abstract) super classes and the actual field name is used instead when the XML document is read; when an object is persisted, however, the @XStreamAlias annotation is used correctly.