JSEC-20 - added JavaDoc and modified code to now throw an IllegalStateException if the SecurityManager is inaccessible, indicating invalid configuration.
JSEC-20 - added JavaDoc and modified code to now throw an IllegalStateException if the SecurityManager is inaccessible, indicating invalid configuration.

git-svn-id: ec6ef1d57ec0831ce4cbff3b75527511e63bfbe3@738002 13f79535-47bb-0310-9956-ffa450edef68

relateiq/shiro,feige712/shiro,apache/shiro,feige712/shiro,apache/shiro