I don't see any behavior change, when I set standard java.security.krb5.* system properties. Trying to set properties in both ways:

• command line

   
  -Djava.security.krb5.conf=/unreal/path  -Djava.security.krb5.debug=true -Djava.security.krb5.kdc=wrong.kdc -Djava.security.krb5.realm=REDHAT.COM
  

• standalone.xml

          <property name="java.security.krb5.conf" value="/etc/krb5.confBUG"/>
          <property name="java.security.krb5.kdc" value="localhost.localhostBUG"/>
          <property name="java.security.krb5.realm" value="JBOSS.ORGBUG"/>
          <property name="java.security.krb5.debug" value="true"/>
  

Biggest problem as I see is user is unable to change krb5.conf location. In legacy security solution it was possible.