Shutdown hooks cannot be modified during shutdown.

      java.lang.IllegalStateException: Shutdown hooks cannot be modified during shutdown.
      at org.apache.spark.util.SparkShutdownHookManager.add(ShutdownHookManager.scala:246)
      at org.apache.spark.util.ShutdownHookManager$.addShutdownHook(ShutdownHookManager.scala:191)
      at org.apache.spark.storage.DiskBlockManager.addShutdownHook(DiskBlockManager.scala:147)
      at org.apache.spark.storage.DiskBlockManager.<init>(DiskBlockManager.scala:54)
      at org.apache.spark.storage.BlockManager.<init>(BlockManager.scala:76)
      at org.apache.spark.SparkEnv$.create(SparkEnv.scala:365)
      at org.apache.spark.SparkEnv$.createDriverEnv(SparkEnv.scala:193)
      at org.apache.spark.SparkContext.createSparkEnv(SparkContext.scala:288)
      at org.apache.spark.SparkContext.<init>(SparkContext.scala:457)
      at org.apache.spark.SparkContext.<init>(SparkContext.scala:147)
      at org.apache.spark.FileServerSuite$$anonfun$11.apply$mcV$sp(FileServerSuite.scala:167)
      at org.apache.spark.FileServerSuite$$anonfun$11.apply(FileServerSuite.scala:166)
      at org.apache.spark.FileServerSuite$$anonfun$11.apply(FileServerSuite.scala:166)
      at org.scalatest.Transformer$$anonfun$apply$1.apply$mcV$sp(Transformer.scala:22)
      at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
      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$$anon$1.apply(FunSuiteLike.scala:166)
      at org.apache.spark.SparkFunSuite.withFixture(SparkFunSuite.scala:42)
      at org.scalatest.FunSuiteLike$class.invokeWithFixture$1(FunSuiteLike.scala:163)
      at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
      at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
      at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
      at org.scalatest.FunSuiteLike$class.runTest(FunSuiteLike.scala:175)
      at org.apache.spark.FileServerSuite.org$scalatest$BeforeAndAfterEach$$super$runTest(FileServerSuite.scala:32)
      at org.scalatest.BeforeAndAfterEach$class.runTest(BeforeAndAfterEach.scala:255)
      at org.apache.spark.FileServerSuite.runTest(FileServerSuite.scala:32)
      at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:208)
      at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:208)
      at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:413)
      at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:401)
      at scala.collection.immutable.List.foreach(List.scala:318)
      at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
      at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:396)
      at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:483)
      at org.scalatest.FunSuiteLike$class.runTests(FunSuiteLike.scala:208)
      at org.scalatest.FunSuite.runTests(FunSuite.scala:1555)
      at org.scalatest.Suite$class.run(Suite.scala:1424)
      at org.scalatest.FunSuite.org$scalatest$FunSuiteLike$$super$run(FunSuite.scala:1555)
      at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:212)
      at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:212)
      at org.scalatest.SuperEngine.runImpl(Engine.scala:545)
      at org.scalatest.FunSuiteLike$class.run(FunSuiteLike.scala:212)
      at org.apache.spark.FileServerSuite.org$scalatest$BeforeAndAfterAll$$super$run(FileServerSuite.scala:32)
      at org.scalatest.BeforeAndAfterAll$class.liftedTree1$1(BeforeAndAfterAll.scala:257)
      at org.scalatest.BeforeAndAfterAll$class.run(BeforeAndAfterAll.scala:256)
      at org.apache.spark.FileServerSuite.run(FileServerSuite.scala:32)
      at org.scalatest.Suite$class.callExecuteOnSuite$1(Suite.scala:1492)
      at org.scalatest.Suite$$anonfun$runNestedSuites$1.apply(Suite.scala:1528)
      at org.scalatest.Suite$$anonfun$runNestedSuites$1.apply(Suite.scala:1526)
      at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
      at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108)
      at org.scalatest.Suite$class.runNestedSuites(Suite.scala:1526)
      at org.scalatest.tools.DiscoverySuite.runNestedSuites(DiscoverySuite.scala:29)
      at org.scalatest.Suite$class.run(Suite.scala:1421)
      at org.scalatest.tools.DiscoverySuite.run(DiscoverySuite.scala:29)
      at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:55)
      at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$3.apply(Runner.scala:2563)
      at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$3.apply(Runner.scala:2557)
      at scala.collection.immutable.List.foreach(List.scala:318)
      at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:2557)
      at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1044)
      at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1043)
      at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:2722)
      at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1043)
      at org.scalatest.tools.Runner$.main(Runner.scala:860)
      at org.scalatest.tools.Runner.main(Runner.scala)