<p>Task not serializable</p>


<pre><code>
      org.apache.spark.SparkException: Task not serializable
      at org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:396)
      at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:386)
      at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:159)
      at org.apache.spark.util.TestCreateNullValue.$anonfun$run$25(ClosureCleanerSuite.scala:376)
      at org.apache.spark.util.TestCreateNullValue.run(ClosureCleanerSuite.scala:378)
      at org.apache.spark.util.ClosureCleanerSuite.$anonfun$new$44(ClosureCleanerSuite.scala:120)
      at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
      at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
      at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
      at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
      at org.scalatest.Transformer.apply(Transformer.scala:22)
      at org.scalatest.Transformer.apply(Transformer.scala:20)
      at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:186)
      at org.apache.spark.SparkFunSuite.withFixture(SparkFunSuite.scala:149)
      at org.scalatest.FunSuiteLike.invokeWithFixture$1(FunSuiteLike.scala:184)
      at org.scalatest.FunSuiteLike.$anonfun$runTest$1(FunSuiteLike.scala:196)
      at org.scalatest.SuperEngine.runTestImpl(Engine.scala:289)
      at org.scalatest.FunSuiteLike.runTest(FunSuiteLike.scala:196)
      at org.scalatest.FunSuiteLike.runTest$(FunSuiteLike.scala:178)
      at org.apache.spark.SparkFunSuite.org$scalatest$BeforeAndAfterEach$$super$runTest(SparkFunSuite.scala:56)
      at org.scalatest.BeforeAndAfterEach.runTest(BeforeAndAfterEach.scala:221)
      at org.scalatest.BeforeAndAfterEach.runTest$(BeforeAndAfterEach.scala:214)
      at org.apache.spark.SparkFunSuite.runTest(SparkFunSuite.scala:56)
      at org.scalatest.FunSuiteLike.$anonfun$runTests$1(FunSuiteLike.scala:229)
      at org.scalatest.SuperEngine.$anonfun$runTestsInBranch$1(Engine.scala:396)
      at scala.collection.immutable.List.foreach(List.scala:392)
      at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:384)
      at org.scalatest.SuperEngine.runTestsInBranch(Engine.scala:379)
      at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:461)
      at org.scalatest.FunSuiteLike.runTests(FunSuiteLike.scala:229)
      at org.scalatest.FunSuiteLike.runTests$(FunSuiteLike.scala:228)
      at org.scalatest.FunSuite.runTests(FunSuite.scala:1560)
      at org.scalatest.Suite.run(Suite.scala:1147)
      at org.scalatest.Suite.run$(Suite.scala:1129)
      at org.scalatest.FunSuite.org$scalatest$FunSuiteLike$$super$run(FunSuite.scala:1560)
      at org.scalatest.FunSuiteLike.$anonfun$run$1(FunSuiteLike.scala:233)
      at org.scalatest.SuperEngine.runImpl(Engine.scala:521)
      at org.scalatest.FunSuiteLike.run(FunSuiteLike.scala:233)
      at org.scalatest.FunSuiteLike.run$(FunSuiteLike.scala:232)
      at org.apache.spark.SparkFunSuite.org$scalatest$BeforeAndAfterAll$$super$run(SparkFunSuite.scala:56)
      at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:213)
      at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
      at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
      at org.apache.spark.SparkFunSuite.run(SparkFunSuite.scala:56)
      at org.scalatest.Suite.callExecuteOnSuite$1(Suite.scala:1210)
      at org.scalatest.Suite.$anonfun$runNestedSuites$1(Suite.scala:1257)
      at scala.collection.IndexedSeqOptimized.foreach(IndexedSeqOptimized.scala:36)
      at scala.collection.IndexedSeqOptimized.foreach$(IndexedSeqOptimized.scala:33)
      at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:198)
      at org.scalatest.Suite.runNestedSuites(Suite.scala:1255)
      at org.scalatest.Suite.runNestedSuites$(Suite.scala:1189)
      at org.scalatest.tools.DiscoverySuite.runNestedSuites(DiscoverySuite.scala:30)
      at org.scalatest.Suite.run(Suite.scala:1144)
      at org.scalatest.Suite.run$(Suite.scala:1129)
      at org.scalatest.tools.DiscoverySuite.run(DiscoverySuite.scala:30)
      at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:45)
      at org.scalatest.tools.Runner$.$anonfun$doRunRunRunDaDoRunRun$13(Runner.scala:1346)
      at org.scalatest.tools.Runner$.$anonfun$doRunRunRunDaDoRunRun$13$adapted(Runner.scala:1340)
      at scala.collection.immutable.List.foreach(List.scala:392)
      at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:1340)
      at org.scalatest.tools.Runner$.$anonfun$runOptionallyWithPassFailReporter$24(Runner.scala:1031)
      at org.scalatest.tools.Runner$.$anonfun$runOptionallyWithPassFailReporter$24$adapted(Runner.scala:1010)
      at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:1506)
      at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1010)
      at org.scalatest.tools.Runner$.main(Runner.scala:827)
      at org.scalatest.tools.Runner.main(Runner.scala)
      Cause: java.io.NotSerializableException: org.apache.spark.util.TestCreateNullValue
Serialization stack:
	- object not serializable (class: org.apache.spark.util.TestCreateNullValue, value: org.apache.spark.util.TestCreateNullValue@3d3e0d08)
	- element of array (index: 0)
	- array (class [Ljava.lang.Object;, size 1)
	- field (class: java.lang.invoke.SerializedLambda, name: capturedArgs, type: class [Ljava.lang.Object;)
	- object (class java.lang.invoke.SerializedLambda, SerializedLambda[capturingClass=class org.apache.spark.util.TestCreateNullValue, functionalInterfaceMethod=scala/runtime/java8/JFunction0$mcV$sp.apply$mcV$sp:()V, implementation=invokeStatic org/apache/spark/util/TestCreateNullValue.$anonfun$run$26:(Lorg/apache/spark/util/TestCreateNullValue;)V, instantiatedMethodType=()V, numCaptured=1])
	- writeReplace data (class: java.lang.invoke.SerializedLambda)
	- object (class org.apache.spark.util.TestCreateNullValue$$Lambda$7910/0x000000080244e440, org.apache.spark.util.TestCreateNullValue$$Lambda$7910/0x000000080244e440@54f64dd5)
      at org.apache.spark.serializer.SerializationDebugger$.improveException(SerializationDebugger.scala:41)
      at org.apache.spark.serializer.JavaSerializationStream.writeObject(JavaSerializer.scala:47)
      at org.apache.spark.serializer.JavaSerializerInstance.serialize(JavaSerializer.scala:101)
      at org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:393)
      at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:386)
      at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:159)
      at org.apache.spark.util.TestCreateNullValue.$anonfun$run$25(ClosureCleanerSuite.scala:376)
      at org.apache.spark.util.TestCreateNullValue.run(ClosureCleanerSuite.scala:378)
      at org.apache.spark.util.ClosureCleanerSuite.$anonfun$new$44(ClosureCleanerSuite.scala:120)
      at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
      at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
      at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
      at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
      at org.scalatest.Transformer.apply(Transformer.scala:22)
      at org.scalatest.Transformer.apply(Transformer.scala:20)
      at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:186)
      at org.apache.spark.SparkFunSuite.withFixture(SparkFunSuite.scala:149)
      at org.scalatest.FunSuiteLike.invokeWithFixture$1(FunSuiteLike.scala:184)
      at org.scalatest.FunSuiteLike.$anonfun$runTest$1(FunSuiteLike.scala:196)
      at org.scalatest.SuperEngine.runTestImpl(Engine.scala:289)
      at org.scalatest.FunSuiteLike.runTest(FunSuiteLike.scala:196)
      at org.scalatest.FunSuiteLike.runTest$(FunSuiteLike.scala:178)
      at org.apache.spark.SparkFunSuite.org$scalatest$BeforeAndAfterEach$$super$runTest(SparkFunSuite.scala:56)
      at org.scalatest.BeforeAndAfterEach.runTest(BeforeAndAfterEach.scala:221)
      at org.scalatest.BeforeAndAfterEach.runTest$(BeforeAndAfterEach.scala:214)
      at org.apache.spark.SparkFunSuite.runTest(SparkFunSuite.scala:56)
      at org.scalatest.FunSuiteLike.$anonfun$runTests$1(FunSuiteLike.scala:229)
      at org.scalatest.SuperEngine.$anonfun$runTestsInBranch$1(Engine.scala:396)
      at scala.collection.immutable.List.foreach(List.scala:392)
      at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:384)
      at org.scalatest.SuperEngine.runTestsInBranch(Engine.scala:379)
      at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:461)
      at org.scalatest.FunSuiteLike.runTests(FunSuiteLike.scala:229)
      at org.scalatest.FunSuiteLike.runTests$(FunSuiteLike.scala:228)
      at org.scalatest.FunSuite.runTests(FunSuite.scala:1560)
      at org.scalatest.Suite.run(Suite.scala:1147)
      at org.scalatest.Suite.run$(Suite.scala:1129)
      at org.scalatest.FunSuite.org$scalatest$FunSuiteLike$$super$run(FunSuite.scala:1560)
      at org.scalatest.FunSuiteLike.$anonfun$run$1(FunSuiteLike.scala:233)
      at org.scalatest.SuperEngine.runImpl(Engine.scala:521)
      at org.scalatest.FunSuiteLike.run(FunSuiteLike.scala:233)
      at org.scalatest.FunSuiteLike.run$(FunSuiteLike.scala:232)
      at org.apache.spark.SparkFunSuite.org$scalatest$BeforeAndAfterAll$$super$run(SparkFunSuite.scala:56)
      at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:213)
      at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
      at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
      at org.apache.spark.SparkFunSuite.run(SparkFunSuite.scala:56)
      at org.scalatest.Suite.callExecuteOnSuite$1(Suite.scala:1210)
      at org.scalatest.Suite.$anonfun$runNestedSuites$1(Suite.scala:1257)
      at scala.collection.IndexedSeqOptimized.foreach(IndexedSeqOptimized.scala:36)
      at scala.collection.IndexedSeqOptimized.foreach$(IndexedSeqOptimized.scala:33)
      at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:198)
      at org.scalatest.Suite.runNestedSuites(Suite.scala:1255)
      at org.scalatest.Suite.runNestedSuites$(Suite.scala:1189)
      at org.scalatest.tools.DiscoverySuite.runNestedSuites(DiscoverySuite.scala:30)
      at org.scalatest.Suite.run(Suite.scala:1144)
      at org.scalatest.Suite.run$(Suite.scala:1129)
      at org.scalatest.tools.DiscoverySuite.run(DiscoverySuite.scala:30)
      at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:45)
      at org.scalatest.tools.Runner$.$anonfun$doRunRunRunDaDoRunRun$13(Runner.scala:1346)
      at org.scalatest.tools.Runner$.$anonfun$doRunRunRunDaDoRunRun$13$adapted(Runner.scala:1340)
      at scala.collection.immutable.List.foreach(List.scala:392)
      at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:1340)
      at org.scalatest.tools.Runner$.$anonfun$runOptionallyWithPassFailReporter$24(Runner.scala:1031)
      at org.scalatest.tools.Runner$.$anonfun$runOptionallyWithPassFailReporter$24$adapted(Runner.scala:1010)
      at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:1506)
      at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1010)
      at org.scalatest.tools.Runner$.main(Runner.scala:827)
      at org.scalatest.tools.Runner.main(Runner.scala)
</code></pre>