Wings - RIA - creation in Java or XML based language

I am quoting here the Wings framework web site.
"Popular frameworks like Sun JSF and Apache Struts rely on a heavy mix of different technologies like Java, JSP, XML & Tag libs. This implies that the association between the different media have to be maintained manually to be always in sync. Errors between these assoication implies bad suprises during runtime while pure Java-based frameworks like Wings can leverage of the compilers consistency checks."

I agree. Most XML based stuff are deferring checks at runtime. By the way this is my single regret with the Spring container and IOC. Fortunately the Spring container parses and validates the XML directive up-front when the application context is created so most errors can be easily checked at start-up.