We have code which extends sun.awt.DisplayChangedListener, and yes we know that it is documented by Oracle as a internal only interface; however, our developers maintain they have no other way to make their code run properly. Since sun.awt is not considered a system package our users run into problems when using Jboss 7.1. And yes we realize that the user can code Djboss.modules.system.pkgs in her conf file; however, that's one more thing to keep track of. And sun.awt really is a system package when using the Oracle JRE.