Running server in C9-google cloud, but couldn't see iit n C9 "Preview"


#1

[info] Running com.example.WebServerHttpApp
Press RETURN to stop…
[INFO] [06/21/2017 16:13:37.681] [WebServerHttpApp-akka.actor.default-dispatcher-2] [akka.actor.ActorSystemImpl(WebServerHttpApp)] Server online at http://localhost:8080/

however
$ curl http://localhost:8080
Server up and running


#2

does your server listen on localhost or 0.0.0.0, only servers listening on 0.0.0.0 are proxied by preview.
You can use preview>show active servers menu item, or netstat -tulpn terminal command, to check that.