https://access.redhat.com/webassets/avalon/d/red_hat_jboss_enterprise_application_platform/7.2/javadocs/javax/xml/bind/annotation/XmlElementRef.html
XmlElementRef (Red Hat JBoss Enterprise Application Platform 7.2.0.GA public API)
red hat jboss
https://docs.oracle.com/javase/8/docs/api/javax/xml/bind/annotation/XmlElementRef.DEFAULT.html
XmlElementRef.DEFAULT (Java Platform SE 8 )
java platformdefaultse