Can't compile 2.2 to 2.3 Migration - scala

Question

I have been fighting with this for the past few hours and I haven't made any headway at all. It seems no matter what I do, I keep getting the same error.
java.lang.NoClassDefFoundError: play/Project$
My build.sbt
name := "appname"
version := "1.0-SNAPSHOT"
libraryDependencies ++= Seq(
jdbc,
anorm,
cache,
filters,
"org.postgresql" % "postgresql" % "9.3-1100-jdbc4",
"org.mindrot" % "jbcrypt" % "0.3m",
"org.webjars" %% "webjars-play" % "2.3.0-2",
"org.webjars" % "foundation" % "5.3.0",
"org.scalaj" %% "scalaj-http" % "0.3.16"
)
lazy val root = (project in file(".")).enablePlugins(PlayScala)
scalaVersion := "2.10.4"
I have also tried this build.sbt
object ApplicationBuild extends Build {
val appName = "appname"
val appVersion = "1.0-SNAPSHOT"
val appDependencies ++= Seq(
jdbc,
anorm,
cache,
filters,
"org.postgresql" % "postgresql" % "9.3-1100-jdbc4",
"org.mindrot" % "jbcrypt" % "0.3m",
"org.webjars" %% "webjars-play" % "2.3.0-2",
"org.webjars" % "foundation" % "5.3.0",
"org.scalaj" %% "scalaj-http" % "0.3.16"
)
val main = Project(appName, file(".")).enablePlugins(play.PlayScala).settings(
scalaVersion := "2.10.4",
version := appVersion,
libraryDependencies ++= appDependencies
)
}
As well as different tweaks and modifications. Always the same error. The build.properties is set to sbt.version=0.13.5
plugins.sbt
logLevel := Level.Debug
// The Typesafe repository
resolvers += "Typesafe repository" at "http://repo.typesafe.com/typesafe/releases/"
// Use the Play sbt plugin for Play projects
addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.3.4")
After running Patrick Mahoney's suggestion and making sure I removed the import.
Errors:
[error] java.lang.NoClassDefFoundError: play/Project$
[error] Use 'last' for the full log.
Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? q
me#me-desktop:~/Projects/appname$ sbt --version
sbt launcher version 0.13.6
me#me-desktop:~/Projects/appname$ find . | grep -r "play.Project"
me#me-desktop:~/Projects/appname$ find . | grep -r "play/Project"

Answer 1

Try cleaning your build project compiled outputs:
rm -rf project/target
or
$> sbt "reload plugins" clean
(in addition to applying James' answer)

Answer 2

Thanks to James and Patrick, but I found the problem. The problem was in the activator-sbt-echo-play-shim.sbt file in the /project directory.
It contained the following:
addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "0.1.1.3")
I created a second blank 2.3.4 app using Activator and it's activator-sbt-echo-play-shim.sbt listed:
addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.5")
So I updated the one in my project to 1.5 and deleted the idea and eclipse .sbts for good measure and the app was finally able to compile. It auotmatically updated the above to:
addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.5.2")
Now I have other, more expected, issues I need to work out (like anorm). But I'm now able to compile it and get those errors to start working them out. I did not think these files were part of the activator/sbt compile, but I guess they were. I thought they were for debugging. But they made the difference and the changes above worked.
Thanks again to everyone for their help.

Answer 3

Make sure you've updated project/build.properties to have sbt version 0.13.5. Then, remove import play.Project._, it's not needed. That should work.