Hi,

I'm getting a ClassNotFoundException at the executor when trying to
register a class for Kryo serialization:

java.lang.reflect.InvocationTargetException
      at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
      at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
      at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
      at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
      at org.apache.spark.SparkEnv$.instantiateClass$1(SparkEnv.scala:243)
      at
org.apache.spark.SparkEnv$.instantiateClassFromConf$1(SparkEnv.scala:254)
      at org.apache.spark.SparkEnv$.create(SparkEnv.scala:257)
      at org.apache.spark.SparkEnv$.createExecutorEnv(SparkEnv.scala:182)
      at org.apache.spark.executor.Executor.<init>(Executor.scala:87)
      at
org.apache.spark.executor.CoarseGrainedExecutorBackend$$anonfun$receiveWithLogging$1.applyOrElse(CoarseGrainedExecutorBackend.scala:61)
      at
scala.runtime.AbstractPartialFunction$mcVL$sp.apply$mcVL$sp(AbstractPartialFunction.scala:33)
      at
scala.runtime.AbstractPartialFunction$mcVL$sp.apply(AbstractPartialFunction.scala:33)
      at
scala.runtime.AbstractPartialFunction$mcVL$sp.apply(AbstractPartialFunction.scala:25)
      at
org.apache.spark.util.ActorLogReceive$$anon$1.apply(ActorLogReceive.scala:53)
      at
org.apache.spark.util.ActorLogReceive$$anon$1.apply(ActorLogReceive.scala:42)
      at scala.PartialFunction$class.applyOrElse(PartialFunction.scala:118)
      at
org.apache.spark.util.ActorLogReceive$$anon$1.applyOrElse(ActorLogReceive.scala:42)
      at akka.actor.Actor$class.aroundReceive(Actor.scala:465)
      at
org.apache.spark.executor.CoarseGrainedExecutorBackend.aroundReceive(CoarseGrainedExecutorBackend.scala:36)
      at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
      at akka.actor.ActorCell.invoke(ActorCell.scala:487)
      at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
      at akka.dispatch.Mailbox.run(Mailbox.scala:220)
      at
akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
      at
scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
      at
scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
      at
scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
      at
scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: org.apache.spark.SparkException: Failed to load class to
register with Kryo
      at
org.apache.spark.serializer.KryoSerializer$$anonfun$2.apply(KryoSerializer.scala:66)
      at
org.apache.spark.serializer.KryoSerializer$$anonfun$2.apply(KryoSerializer.scala:61)
      at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
      at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
      at
scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
      at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108)
      at
scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
      at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108)
      at
org.apache.spark.serializer.KryoSerializer.<init>(KryoSerializer.scala:61)
      ... 28 more
Caused by: java.lang.ClassNotFoundException: com.example.Schema$MyRow
      at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:190)
      at
org.apache.spark.serializer.KryoSerializer$$anonfun$2.apply(KryoSerializer.scala:63)

I have verified that when the executor process is launched, my jar is in
the classpath of the command line of the executor.  I expect the class to
be found by the default classloader being used at KryoSerializer.scala:63

Any ideas?

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