I am a new user for the Jboss. I found the Jboss doc said sun.jdk module is loaded automatically by default. But when I deoply a ear file that use com.sun.security.auth.* classes, the program throws exceptions " No calss found". I have to put sun.jdk module into our module.xml configuration. The classes are loaded finally. So I am confused why sun.jdk is not loaded as Doc said.