Scala only project does not start neo4jplugin

[unterstein]

Hi Sepp,

my scala only projects do not start after updating to current version.

I think spring does not start if no java class is found.

Reproduce:

Take examples project and delete JavaController (and adapt routes):

[error] - application -

! @6no07dp09 - Internal server error, for (GET) [/] ->

play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[NullPointerException: null]]
at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:265) ~[play_2.11.jar:2.4.2]
at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:191) ~[play_2.11.jar:2.4.2]
at play.api.GlobalSettings$class.onError(GlobalSettings.scala:179) [play_2.11.jar:2.4.2]
at play.api.DefaultGlobal$.onError(GlobalSettings.scala:212) [play_2.11.jar:2.4.2]
at play.api.http.GlobalSettingsHttpErrorHandler.onServerError(HttpErrorHandler.scala:94) [play_2.11.jar:2.4.2]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$9$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:158) [play-netty-server_2.11.jar:2.4.2]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$9$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:155) [play-netty-server_2.11.jar:2.4.2]
at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:36) [scala-library.jar:na]
at scala.util.Failure$$anonfun$recover$1.apply(Try.scala:215) [scala-library.jar:na]
at scala.util.Try$.apply(Try.scala:191) [scala-library.jar:na]
at scala.util.Failure.recover(Try.scala:215) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$recover$1.apply(Future.scala:324) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$recover$1.apply(Future.scala:324) [scala-library.jar:na]
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32) [scala-library.jar:na]
at play.api.libs.iteratee.Execution$trampoline$.executeScheduled(Execution.scala:109) [play-iteratees_2.11.jar:2.4.2]
at play.api.libs.iteratee.Execution$trampoline$.execute(Execution.scala:71) [play-iteratees_2.11.jar:2.4.2]
at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:40) [scala-library.jar:na]
at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:248) [scala-library.jar:na]
at scala.concurrent.Promise$class.complete(Promise.scala:55) [scala-library.jar:na]
at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:153) [scala-library.jar:na]
at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:23) [scala-library.jar:na]
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40) [akka-actor_2.11.jar:na]
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:397) [akka-actor_2.11.jar:na]
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library.jar:na]
Caused by: java.lang.NullPointerException: null
at neo4jplugin.Neo4jPlugin.get(Neo4jPlugin.java:68) ~[play-neo4jplugin_2.11-1.5.0.jar:1.5.0]
at controllers.Neo4jTransactionAction.apply(scala.scala:21) ~[play-neo4jplugin_2.11-1.5.0.jar:2.4.2]
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:105) ~[play_2.11.jar:2.4.2]
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:105) ~[play_2.11.jar:2.4.2]
at play.utils.Threads$.withContextClassLoader(Threads.scala:21) ~[play_2.11.jar:2.4.2]
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4.apply(Action.scala:104) ~[play_2.11.jar:2.4.2]
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4.apply(Action.scala:103) ~[play_2.11.jar:2.4.2]
at scala.Option.map(Option.scala:146) ~[scala-library.jar:na]
at play.api.mvc.Action$$anonfun$apply$1.apply(Action.scala:103) ~[play_2.11.jar:2.4.2]
at play.api.mvc.Action$$anonfun$apply$1.apply(Action.scala:96) ~[play_2.11.jar:2.4.2]
at play.api.libs.iteratee.DoneIteratee$$anonfun$mapM$2.apply(Iteratee.scala:741) ~[play-iteratees_2.11.jar:2.4.2]
at play.api.libs.iteratee.DoneIteratee$$anonfun$mapM$2.apply(Iteratee.scala:741) ~[play-iteratees_2.11.jar:2.4.2]
at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24) [scala-library.jar:na]
at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24) [scala-library.jar:na]
... 6 common frames omitted

[unterstein]

Solved it - for a single project - with a cruel hack:

class Global extends GlobalSettings {


  val hooks = new util.ArrayList[Callable[Promise[Void]]]()

  override def onStart(app: Application): Unit = {
    super.onStart(app)
    new Neo4jPlugin(new ApplicationLifecycle {
      override def addStopHook(hook: Callable[Promise[Void]]): Unit = hooks.add(hook)
    })
  }

  override def onStop(app: Application): Unit = {
    super.onStop(app)
    hooks.map(f => f.call())
  }
}