The properties service (configured in properties-service.xml) in JBoss application server lets you specify external .properties files that are loaded and can then be accessed as system properties from the deployed applications.
(See here http://community.jboss.org/wiki/PropertiesService for more info...)
Is it also possible to load config files in the .xml format instead of .properties?
I know it is possible for certain given configs like for example the mail-service.xml and the jboss-log4j.xml... But they are both loaded directly by JBoss, and not via the properties service.
This might be possible. The PropertieServices uses the java.util.Properties class, which contains a loadFromXml method. Perhaps you could extend the properties service? Here is some additional info: http://www.webreference.com/programming/Globalize-Web-Applications15_Java6/
Here is some more detailed information on how the SystemProperties service works: http://docs.jboss.org/jbossas/jboss4guide/r4/html/ch10.html
As you may know, you can use either name=value pairs in a .properties file, or a comma-separated list of URL strings in the service descriptor.
Why do you want to use a .xml file instead of .properties?