Is it possible to delploy an application without placing it in the
JBOSS_HOME\server\default\deploy
If possible, then how to make a reference to the application from jboss ???

In tomcat, it is very easy, suppose the application is at E:\Bidla, then i place Bidla.xml in TOMCAT_HOME\conf\Catalina\localhost with the contents of Bidla.xml as follows:

<?xml version='1.0' encoding='utf-8'?>
<Context docBase="E:/Bidla" path="/Bidla" debug="0" reloadable="true"/>