My First Akka project in IntelliJ from scratch. Compile dependency error.

Question

Every now and then I start things from scratch to make sure I know what all the intricate details of setting up a project are. I have a simple app like the following but I get some dependency issues that don't seem to point me anywhere. I'm using scala verions 2.11.

My SBT:

name := "Helios"

version := "1.0"

scalaVersion := "2.11.8"

resolvers += "Typesafe Repository" at "http://repo.typesafe.com/typesafe/releases/"

libraryDependencies ++= Seq(
  "com.typesafe.akka" % "akka-actor" % "2.0.2",
  "com.typesafe.akka" % "akka-slf4j" % "2.0.5")

My Sample Class

import com.echostar.ese.helios.core.Asset
import akka.actor._

class NSPSG extends Actor {

  def receive = {
    case a: Asset => {
      println(s"NSPSG Received asset: ${a}")
    }
    case _ => println("Unexpected message received")
  }
}

(Asset class is just a case class with id and title in it.)

Error Message:

C:\PROJECTS\active\Helios>sbt compile
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
[info] Loading global plugins from C:\Users\dana.murad\.sbt\0.13\plugins
[info] Loading project definition from C:\PROJECTS\active\Helios\project
[info] Set current project to Helios (in build file:/C:/PROJECTS/active/Helios/)
[info] Updating {file:/C:/PROJECTS/active/Helios/}helios...
[info] Resolving jline#jline;2.12.1 ...
[info] Done updating.
[info] Compiling 3 Scala sources to C:\PROJECTS\active\Helios\target\scala-2.11\classes...
[error] missing or invalid dependency detected while loading class file 'package.class'.
[error] Could not access type ScalaObject in package scala,
[error] because it (or its dependencies) are missing. Check your build definition for
[error] missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
[error] A full rebuild may help if 'package.class' was compiled against an incompatible version of scala.
[error] missing or invalid dependency detected while loading class file 'Actor.class'.
[error] Could not access type ScalaObject in package scala,
[error] because it (or its dependencies) are missing. Check your build definition for
[error] missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
[error] A full rebuild may help if 'Actor.class' was compiled against an incompatible version of scala.
[error] C:\PROJECTS\active\Helios\src\main\scala\com\echostar\ese\helios\workers\NSPSG.scala:9: illegal inheritance;
[error]  self-type com.echostar.ese.helios.workers.NSPSG does not conform to akka.actor.Actor's selftype akka.actor.Actor
[error] class NSPSG extends Actor {
[error]                     ^
[error] three errors found
[error] (compile:compileIncremental) Compilation failed
[error] Total time: 3 s, completed Apr 4, 2016 9:19:45 AM

My main App is just a println for now. It's not even calling this actor.

Am I using the wrong version of akka with scala 2.11? -Ylog-classpath didn't help

Is there a reason you are using 2.0.2 and not 2.4.3 (current stable)? — Robert Horvick
experimentation, I tried using 2.4.0. But I resolved it. For some reason it works now. I'll clarify in my answer below... — dlite922

dlite922 dlite922 · Accepted Answer · 2016-04-04T16:18:36

Don't know what fixed it but here's a list of things I did and the project compiles now.

Changed akka dependency line to this (added double percent and changed version back to 2.4)
```
libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor" % "2.4.0"
)
```
Removed my Run configuration and added it back again. ( I think the path to main showed as red (invalid) so redoing it helped resolve it. I changed my package name and I don't think intelliJ picked up the rename well in build-conf)
Started another test project from IntelliJ menu (Akka Main in Scala) and that took a bit to download all dependencies. So maybe my project needed those and wasn't download them?
Removed commented out lines (got rid of a semi-colon). I don't think this did anything but full disclosure, technically I did touch the code even though my actor definition is exactly the same.

My First Akka project in IntelliJ from scratch. Compile dependency error.

1 Answers