Play Framework For Scala: Compilation error[type Application is not a member of package controllers]

Question

I try to compile a scala example in the book: "Play for Scala" but get a following compilation error on Play console:

C:\Play\exp\ch6_implicits>activator run
[info] Loading project definition from C:\Play\exp\ch6_implicits\project
[info] Set current project to ch6_implicits (in build file:/C:/Play/exp/ch6_implicits/)

--- (Running the application, auto-reloading is enabled) ---

[info] p.a.l.c.ActorSystemProvider - Starting application default Akka system: application
[info] p.c.s.NettyServer$ - Listening for HTTP on /0:0:0:0:0:0:0:0:9000

(Server started, use Ctrl+D to stop and go back to the console...)

[info] Compiling 13 Scala sources and 1 Java source to C:\Play\exp\ch6_implicits\target\scala-2.11\classes...
[error] C:\Play\exp\ch6_implicits\conf\routes:6: type Application is not a member of package controllers
[error] GET             /                               controllers.Application.index
[error] C:\Play\exp\ch6_implicits\conf\routes:7: type Shop is not a member of package controllers
[error] GET             /catalog                controllers.Shop.catalog
[error] C:\Play\exp\ch6_implicits\conf\routes:6: type Application is not a member of package controllers
[error] GET             /                               controllers.Application.index
[error] C:\Play\exp\ch6_implicits\conf\routes:7: type Shop is not a member of package controllers
[error] GET             /catalog                controllers.Shop.catalog
[error] C:\Play\exp\ch6_implicits\conf\routes:6: type Application is not a member of package controllers
[error] GET             /                               controllers.Application.index
[error] C:\Play\exp\ch6_implicits\conf\routes:7: type Shop is not a member of package controllers
[error] GET             /catalog                controllers.Shop.catalog
[error] 6 errors found
[error] (compile:compileIncremental) Compilation failed
[error] application -

! @6mafk6inc - Internal server error, for (GET) [/products/new] ->

play.sbt.PlayExceptions$CompilationException: Compilation error[type Application is not a member of package controllers]
        at play.sbt.PlayExceptions$CompilationException$.apply(PlayExceptions.scala:27) ~[na:na]
        at play.sbt.PlayExceptions$CompilationException$.apply(PlayExceptions.scala:27) ~[na:na]
        at scala.Option.map(Option.scala:145) ~[scala-library-2.11.6.jar:na]
        at play.sbt.run.PlayReload$$anonfun$taskFailureHandler$1.apply(PlayReload.scala:49) ~[na:na]
        at play.sbt.run.PlayReload$$anonfun$taskFailureHandler$1.apply(PlayReload.scala:44) ~[na:na]
        at scala.Option.map(Option.scala:145) ~[scala-library-2.11.6.jar:na]
        at play.sbt.run.PlayReload$.taskFailureHandler(PlayReload.scala:44) ~[na:na]
        at play.sbt.run.PlayReload$.compileFailure(PlayReload.scala:40) ~[na:na]
        at play.sbt.run.PlayReload$$anonfun$compile$1.apply(PlayReload.scala:17) ~[na:na]
        at play.sbt.run.PlayReload$$anonfun$compile$1.apply(PlayReload.scala:17) ~[na:na]

Application.scala is:

package controllers

import play.api._
import play.api.mvc._

// We extend the 'WithCart' trait, so we have an implicit conversion from RequestHeader to Cart
object Application extends Controller with WithCart {

  def index = Action { implicit request =>
    // The index template takes an implicit Cart, which is not available.
    // However, the WithCart trait has an implicit conversion from
    // RequestHeader to Cart, and we do have an implicit RequestHeader
    // here, because `request` is a Request, which extends RequestHeader.
    Ok(views.html.index())
  }

  def contact = Action { implicit request =>
    Ok(views.html.contact())
  }

}       

Shop.scala is

package controllers

import play.api._
import play.api.mvc._
import models._

object Shop extends Controller with WithCart {

  def catalog() = Action { implicit request =>
    val products = ProductDAO.list
    Ok(views.html.products.catalog(products))
  }

}

And routes file is:

# Routes
# This file defines all application routes (Higher priority routes first)
# ~~~~

# Home page
GET     /               controllers.Application.index
GET     /catalog        controllers.Shop.catalog
GET     /contact        controllers.Application.contact

# Map static resources from the /public folder to the /assets URL path
GET     /assets/*file               controllers.Assets.at(path="/public", file)

Play Framework is 2.4.0 and about says:

[ch6_implicits] $ about
[info] This is sbt 0.13.8
[info] The current project is {file:/C:/Play/exp/ch6_implicits/}root 1.0-SNAPSHOT
[info] The current project is built against Scala 2.11.6
[info] Available Plugins: sbt.plugins.IvyPlugin, sbt.plugins.JvmPlugin, sbt.plugins.CorePlugin, sbt.plugins.JUnitXmlReportPlugin, play.sbt.Play, play.sbt.PlayAkkaHttpServer, play.sbt.PlayJava, play.sb
t.PlayLayoutPlugin, play.sbt.PlayNettyServer, play.sbt.PlayScala, play.sbt.routes.RoutesCompiler, play.twirl.sbt.SbtTwirl, com.typesafe.sbt.SbtNativePackager, com.typesafe.sbt.packager.archetypes.Akka
AppPackaging, com.typesafe.sbt.packager.archetypes.JavaAppPackaging, com.typesafe.sbt.packager.archetypes.JavaServerAppPackaging, com.typesafe.sbt.packager.archetypes.jar.ClasspathJarPlugin, com.types
afe.sbt.packager.archetypes.jar.LauncherJarPlugin, com.typesafe.sbt.packager.debian.DebianDeployPlugin, com.typesafe.sbt.packager.debian.DebianPlugin, com.typesafe.sbt.packager.debian.JDebPackaging, c
om.typesafe.sbt.packager.docker.DockerPlugin, com.typesafe.sbt.packager.jdkpackager.JDKPackagerDeployPlugin, com.typesafe.sbt.packager.jdkpackager.JDKPackagerPlugin, com.typesafe.sbt.packager.linux.Li
nuxPlugin, com.typesafe.sbt.packager.rpm.RpmDeployPlugin, com.typesafe.sbt.packager.rpm.RpmPlugin, com.typesafe.sbt.packager.universal.UniversalDeployPlugin, com.typesafe.sbt.packager.universal.Univer
salPlugin, com.typesafe.sbt.packager.windows.WindowsDeployPlugin, com.typesafe.sbt.packager.windows.WindowsPlugin, com.typesafe.sbt.web.SbtWeb, com.typesafe.sbt.jse.SbtJsEngine, com.typesafe.sbt.jse.S
btJsTask, com.typesafe.sbt.coffeescript.SbtCoffeeScript, com.typesafe.sbt.less.SbtLess, com.typesafe.sbt.jshint.SbtJSHint, com.typesafe.sbt.rjs.SbtRjs, com.typesafe.sbt.digest.SbtDigest, com.typesafe.
sbt.mocha.SbtMocha, com.typesafe.sbteclipse.plugin.EclipsePlugin
[info] sbt, sbt plugins, and build definitions are using Scala 2.10.4
[ch6_implicits] $

And Java version is:

C:\Play\exp\ch6_implicits>java -version
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)

C:\Play\exp\ch6_implicits>javac -version
javac 1.8.0_45

Any ideas what's the problem and how to fix this?

So far other examples have compiled and run without error in my environment.

Thank you for your support!

Gravettian

Answer 1

Play 2.4, by default, generates a dependency injected router, unlike previously, when it used a static router. You have two options, remove the routesGenerator line from build.sbt so play will generate a static router, or (better) make your controllers classes instead of objects, and use dependency injection.

Repugnance

And what is the philosophy behind this (yet another) breaking change? – Doublespace

Actually, it's not a breaking change, since it's only the default for new projects - existing projects use a static router, and have to explicitly opt in to a DI router. The philosophy is that global state is really bad, it makes testing difficult, and makes it harder to reason about your application. A static router forces global state. – Repugnance

A self contained simple example would be most welcome, I didn't upvote because now I have to lookup somewhere else how to do the controller injection – Ugly

So this definitely deserves a question of its own: Now that we don't have global state is that bad? My actor seemed to be re-created each time we make a request. Is there a way to hold on to state within the Controller? – Cyanotype

To inject to controller add a '@' in front of the function definition in your router and make the Controller a class. ex: GET /index @controllers.Application.index playframework.com/documentation/2.4.x/… – Cyanotype

Changing the build.sbt file looks to be better as I had problems during test when I change the application to be a class instead of an object – Bouquet

play 2.5.x remove static from methods inside controller. – Khosrow

Answer 2

remove routesGenerator := InjectedRoutesGenerator from yout file build.sbt and all will work

Succor

Answer 3

Change your object to a class like this:

object Shop extends Controller with WithCart {
class Shop extends Controller with WithCart {

object Application extends Controller with WithCart {
class Application extends Controller with WithCart {

Directoire

Answer 4

Include below code into into your conf/application.conf file:

play.allowGlobalApplication = true

Newsworthy