End of the test akka null pointer exception has been thrown :
[GatlingSystem-akka.actor.default-dispatcher-2] [akka.actor.ActorSystemImpl(GatlingSystem)] exception while executing timer task
java.lang.NullPointerException
at io.gatling.core.akka.BaseActor.system(BaseActor.scala:27)
at io.gatling.graphite.sender.TcpSender.askForConnection(TcpSender.scala:102)
at io.gatling.graphite.sender.TcpSender$$anonfun$1.$anonfun$applyOrElse$1(TcpSender.scala:57)
at akka.actor.Scheduler$$anon$4.run(Scheduler.scala:205)
at akka.actor.LightArrayRevolverScheduler$TaskHolder.run(LightArrayRevolverScheduler.scala:337)
at akka.actor.LightArrayRevolverScheduler.$anonfun$close$1(LightArrayRevolverScheduler.scala:141)
at akka.actor.LightArrayRevolverScheduler.$anonfun$close$1$adapted(LightArrayRevolverScheduler.scala:140)
at scala.collection.Iterator.foreach(Iterator.scala:941)
at scala.collection.Iterator.foreach$(Iterator.scala:941)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1429)
at scala.collection.IterableLike.foreach(IterableLike.scala:74)
at scala.collection.IterableLike.foreach$(IterableLike.scala:73)
at scala.collection.AbstractIterable.foreach(Iterable.scala:56)
at akka.actor.LightArrayRevolverScheduler.close(LightArrayRevolverScheduler.scala:140)
at akka.actor.ActorSystemImpl.stopScheduler(ActorSystem.scala:937)
at akka.actor.ActorSystemImpl.$anonfun$_start$1(ActorSystem.scala:872)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at akka.actor.ActorSystemImpl$$anon$3.run(ActorSystem.scala:892)
at akka.actor.ActorSystemImpl$TerminationCallbacks$$anonfun$addRec$1$1.applyOrElse(ActorSystem.scala:1068)
at akka.actor.ActorSystemImpl$TerminationCallbacks$$anonfun$addRec$1$1.applyOrElse(ActorSystem.scala:1068)
at scala.concurrent.Future.$anonfun$andThen$1(Future.scala:536)
at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:33)
at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:33)
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:91)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:85)
at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:91)
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:44)
at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)