[2.4.0] java.lang.NoClassDefFoundError: play/Play$

[Fong Huang Yee]

I just updated to latest play 2.4.0. I try using activator ui, but i receive the error as below. Anyone facing same issue here?

• Done updating.
• play/Play$
• java.lang.NoClassDefFoundError: play/Play$
• Use 'last' for the full log.
• Failed to load project.

[Fong Huang Yee]

Notice that play-fork-run.sbt 

addSbtPlugin("com.typesafe.play" % "sbt-fork-run-plugin" % "2.3.8")

Change to

addSbtPlugin("com.typesafe.play" % "sbt-fork-run-plugin" % "2.4.0")

Then project will be able to build.

[Allan Cochrane]

Hi,

tried that but activator ui just overwrote it with 2.3.8 again!

How did this work for you?

Allan

[James Roper]

For now you'll have to not use the Activator ui, until we fix this in Activator.

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[Mark Liu]

Just confirming that I also see this error when trying to build a new project from the Scala Play seed. Is there a related github issue filed for this?

[Mats B]

Manually changing:

  addSbtPlugin("com.typesafe.play" % "sbt-fork-run-plugin" % "2.3.8")

to:

  addSbtPlugin("com.typesafe.play" % "sbt-fork-run-plugin" % "2.4.0")

in "play-fork.run.sbt" made it possible to build the application.

When trying "activator ui" the invalid version reference was restored and so the project once again failed to build (as noted previously).

I also noted in the IDE Configuration documentation for the Eclipse IDE that the line:

  addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "4.0.0")

should be added to the plugins.sbt file, But it seems this currently has to be:

  addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "4.0.0-RC2")

for the dependecy to work correctly.

But since the command line option to create an Eclipse project ("activator eclipse") seems to be gone (?) the "activator ui" really is needed for me to be able to work with the code in a sensible manner. Hoping for a quick fix to the activator :)

Cheers!

/Mats

[Ian Rae]

Thanks Mats.  This issue plus my rural internet just cost hours in installing 2.4.  But now it works :)

--Ian
 

[Matthias Kurz]

Someone opend a releated issue on github just now:

https://github.com/playframework/playframework/issues/4595

[Toby Hobson]

I'm having the same issues. Has anyone found a way to run the 2.3x version? It seems all the 2.3x download links point to the same (current) activator package

[Pan Lu]

Hey Allan,

Sorry just ran into the problem.  I end up putting this line

addSbtPlugin("com.typesafe.play" % "sbt-fork-run-plugin" % "2.4.0")

into the plugins.sbt file located in the project folder.  While in the project folder, delete play-fork-run.sbt file as well.

Pan