I am user jbossAS jboss-4.0.2

In my app, i put one resource file (xyz.properties) in $jboss.server.home.dir/conf! my webapp while load it by thread context classpath,then I deploy my war in $jboss.server.home.dir/deploy,everything is ok,but when I re-deploy this war,I found the $jboss.server.home.dir/conf/xyz.properties can't found and throws FileNotFountException ,I read doc about jboss classload,but can't explain ......who can tell me the theory about the redeploy rules....thx very much.