I know, that this is an quite old discussion, but I want to add my findings too. One year ago I deployed a JSF appliction on a Tomcat 7 instance and everything worked fine. Today I',m trying to make the same unmodified JSF appliction up an running on JBoss AS7.1 Unfortunately I now get the same error: Class javax.el.BeanELResolver can not access a member of class java.util.Collections$UnmodifiableCollection with modifiers "public"*
Because of this discussion I know how to solve this problem, but it didn't turned out here why it's it that way. Why a ServletRunner is able to while an ApplicationServer isn't ?