Marks a property that refers to classes with XmlElement or JAXBElement.

Compared to an element property (property with XmlElement annotation), a reference property has a different substitution semantics. When a sub-class is assigned to a property, an element property produces the same tag name with @xsi:type, whereas a reference property produces a different tag name (the tag name that's on the the sub-class.)

This annotation can be used with the following annotations: XmlJavaTypeAdapter, XmlElementWrapper.