Aren't you asking about how to call the application that is running on the jboss server cluster from client ? If yes, then following is what I know about that thing.
Suppose your application is deployed on the cluster. There is a concept called HA-JNDI in JBoss that, I think, isn't a standard in application server specification.
In order to call your application on the JBoss server and to utilize the full functionality of clustering mechanism, you need to call the HA-JNDI on the nodes of the server. But HA-JNDI (i think) doesn't have knowledge of the nodes that are part of the cluster so you need to specify all those node names in the URL you use to connect to the server and use the port no that is given by HA-JNDI.
let node1.com and node2.com are the IP-Address of the machines on which JBoss is running and are part of the cluster, then from within client you would use
String url = "java://node1.com/1100,java://node2.com/1100";
Hope that helps.