I have tested a play 2.3.4 app, and in the console it complains the following:
! @6jg7imio5 - Internal server error, for (GET) [/favicon.ico] ->
play.api.App
Every browser looks for favicon.ico
when visiting the address. Just add that file to your public
folder and add a route:
GET /favicon.ico controllers.Assets.at(path="/public", file="favicon.ico")
TIP: it can be also png file - in default new PlayJava or PlayScala project it can be found in public/images/favicon.png
you should denote the path as controllers.Assets.at(path="/public/images", file="favicon.ico")