You can place the service-location details of a web service in the EGL deployment descriptor and then specify the Resource annotation when you declare a service-access variable.
The Resource annotation refers to an entry in the EGL deployment description, specifically, to an entry in the resource bindings section of the EGL deployment descriptor.
If you change the URI template, you must change it in the Interface part and redeploy the code internally. You cannot include the template in a runtime configuration file because the template generally includes values that are set at run time.
You can access a third-party REST service by specifying all the details in either the URI or a URI template.