Use Service.doInvoke() to call pub.client:http, if you really want to do what you’re doing from a Java service.
I assume you’re doing some simple proof of concept since calling addInt remotely seems a bit odd to do for real. 
I would recommend not using pub.remote:invoke. Nor doing such a call in a Java service.
Use the provided pub.client:http to do the work, that way your solution is not assuming that the called component is hosted on another IS.
Is there a specific reason you need to do this from a Java service?
#Flow-and-Java-services#Integration-Server-and-ESB#webMethods