Integration of 3rd Party Java Application System

Hello -

A customer has a non-SAP J2EE Application Server (BEA Weblogic) and would like to know the best means of integrating to XI. Looking at XI documentation, it's unclear whether the Java Proxy Runtime (JPR) and Java Proxy Server are supported on non-SAP J2EE Application Servers. First, is JPR and Java Proxy Server only supported for SAP J2EE Engine? Second, what is the recommended way of integrating 3rd party J2EE systems with XI?

Thanks.

Jin