In previous posts I have covered how to map inheritance relationships in JAXB. This can be done by element name (via @XmlElementRef), by the xsi:type attribute, or in EclipseLink MOXy using another XML attribute (via @XmlDescriminatorNode/@XmlDescriminatorValue). In this post the type indicator will be an XML attribute/element unique to that type, and we will leverage an XmlAdapter to implement this behaviour.