There is no link to do that, but you could write some code that gets the classes for each classlaoder, combines them into one list (without duplicates) and displays that list.

Or, check if you could do this on CL domain. Less items to check; number of domains << number of classloaders.

http://anonsvn.jboss.org/repos/jbossas/projects/jboss-cl/trunk/classloader/src/main/java/org/jboss/classloader/spi/ClassLoaderDomainMBean.java