Session EJBs provide remote invocation services. They are clustered based on the client-side interceptor architecture. The client application for a clustered session bean is exactly the same as the client for the non-clustered version of the session bean, except for a minor change to the java.naming.provier.url system property to enable HA-JNDI lookup (see previous section). No code change or re-compilation is needed on the client side. Now, let's check out how to configure clustered session beans in EJB 2.x and EJB 3.0 server applications respectively.