Hi, I think I'm running into an Akka version conflict when running a Flink job on a cluster.
The current situation: - Flink cluster on Flink 1.4.2 (using Docker) - Flink job which uses twitter4s [1] library and Akka version 2.5.8 In my Flink job I try to 'shutdown' an Akka actor from the twitter4s library. This results in a whole taskmanager crashing with the following stacktrace: taskrunner_1 | 2018-06-11 09:03:14,454 INFO org.apache.flink.runtime.taskmanager.TaskManager - Un-registering task and sending final execution state CANCELED to JobManager for task Source: Custom Source -> Sink: Unnamed (0ba7f7f259eee06fe2f7d783c868179b) taskrunner_1 | Uncaught error from thread [twitter4s-streaming-akka.actor.default-dispatcher-288]: loader constraint violation: when resolving method "akka.actor.ActorCell$$anonfun$3.<init>(Lakka/actor/ActorCell;)V" the class loader (instance of org/apache/flink/runtime/execution/librarycache/FlinkUserCodeClassLoaders$ChildFirstClassLoader) of the current class, akka/actor/ActorCell, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, akka/actor/ActorCell$$anonfun$3, have different Class objects for the type akka/actor/ActorCell used in the signature, shutting down JVM since 'akka.jvm-exit-on-fatal-error' is enabled for for ActorSystem[twitter4s-streaming] taskrunner_1 | java.lang.LinkageError: loader constraint violation: when resolving method "akka.actor.ActorCell$$anonfun$3.<init>(Lakka/actor/ActorCell;)V" the class loader (instance of org/apache/flink/runtime/execution/librarycache/FlinkUserCodeClassLoaders$ChildFirstClassLoader) of the current class, akka/actor/ActorCell, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, akka/actor/ActorCell$$anonfun$3, have different Class objects for the type akka/actor/ActorCell used in the signature taskrunner_1 | at akka.actor.ActorCell.invoke(ActorCell.scala:499) taskrunner_1 | at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257) taskrunner_1 | at akka.dispatch.Mailbox.run(Mailbox.scala:224) taskrunner_1 | at akka.dispatch.Mailbox.exec(Mailbox.scala:234) taskrunner_1 | at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) taskrunner_1 | at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) taskrunner_1 | at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) taskrunner_1 | at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) taskrunner_1 | 2018-06-11 09:03:14,984 INFO org.apache.flink.runtime.blob.PermanentBlobCache - Shutting down BLOB cache taskrunner_1 | 2018-06-11 09:03:14,985 INFO org.apache.flink.runtime.blob.TransientBlobCache - Shutting down BLOB cache taskrunner_1 | Exception in thread "twitter4s-streaming-shutdown-hook-1" java.lang.NoClassDefFoundError: akka/actor/CoordinatedShutdown$$anonfun$totalTimeout$1 taskrunner_1 | at akka.actor.CoordinatedShutdown.totalTimeout(CoordinatedShutdown.scala:515) taskrunner_1 | at akka.actor.CoordinatedShutdown$$anonfun$initJvmHook$1.apply(CoordinatedShutdown.scala:217) taskrunner_1 | at akka.actor.CoordinatedShutdown$$anon$2.run(CoordinatedShutdown.scala:547) taskrunner_1 | Caused by: java.lang.ClassNotFoundException: akka.actor.CoordinatedShutdown$$anonfun$totalTimeout$1 taskrunner_1 | at java.net.URLClassLoader.findClass(URLClassLoader.java:381) taskrunner_1 | at java.lang.ClassLoader.loadClass(ClassLoader.java:424) taskrunner_1 | at org.apache.flink.runtime.execution.librarycache.FlinkUserCodeClassLoaders$ChildFirstClassLoader.loadClass(FlinkUserCodeClassLoaders.java:128) taskrunner_1 | at java.lang.ClassLoader.loadClass(ClassLoader.java:357) taskrunner_1 | ... 3 more To me, it looks like an version conflict. Any suggestions how to solve this? Thanks! Wouter [1] - Twitter4s: https://github.com/DanielaSfregola/twitter4s/blob/master/build.sbt
