We had a problem mapping subclasses of java.lang.Exception in XML using JAXB 2.1. In particular, JAXB tried to map Exception.stackTrace field and failed with the following error: IllegalAnnotationsException: "java.lang.StackTraceElement does not have a no-arg default constructor".
Luckily JBoss JAXBIntroductions provided us a workaround. Once I added support for @XmlTransient annotation I was able to annotate Exception with @XmlTransient in JaxbIntros meta data. (Another way may be annotating Throwable.stackTrace).
Can I contribute to JaxbIntros project by submitting @XmlTransient support (XmlTransientHandler and XmlTransientIntro) into SVN?
That sounds great and we'd be more than happy to accept your additions.
Easiest thing to do for now is to package up your changes (in an SVN patch file if possible) and attach them to a new feature request JIRA at http://jira.jboss.com/jira/browse/JBESB.