default
This template is mainly for Maven code-gen plugin use-case - when
Swagger spec on existing project changes there is no need to manually
copy/paste the new functions from the generated client. This will
provide a default (empty) implementation to existing impl and user just
need to override the stub implementation.
Because it generates an interface instead of a concrete stub, an
implementation will be needed to actuate a service end-point. And don't
forget to put @Controller on the implementation!
