I created a property file and placed it inside a jar file and changed the classpath of the jboss server. (opened run.bat and set CLASSPATH variable)
I could able to see the updated classpath when I do run --help at command prompt.
the JBOSS CLASSPATH contains:jboss_home\bin\run.jar;custom_jar_home\serverconfig.jar
From my web application I did like this.
ClassLoader.getSystemClassLoader().getResource("serverconfig.properties").getPath()