java.lang.IllegalStateException: Shutdown hooks cannot be modified during shutdown.
sbt.ForkMain$ForkError: java.lang.IllegalStateException: Shutdown hooks cannot be modified during shutdown.
at org.apache.spark.util.SparkShutdownHookManager.add(ShutdownHookManager.scala:195)
at org.apache.spark.util.ShutdownHookManager$.addShutdownHook(ShutdownHookManager.scala:153)
at org.apache.spark.storage.DiskBlockManager.addShutdownHook(DiskBlockManager.scala:154)
at org.apache.spark.storage.DiskBlockManager.<init>(DiskBlockManager.scala:51)
at org.apache.spark.storage.BlockManager.<init>(BlockManager.scala:142)
at org.apache.spark.SparkEnv$.create(SparkEnv.scala:351)
at org.apache.spark.SparkEnv$.createDriverEnv(SparkEnv.scala:185)
at org.apache.spark.SparkContext.createSparkEnv(SparkContext.scala:259)
at org.apache.spark.SparkContext.<init>(SparkContext.scala:429)
at org.apache.spark.SparkContext$.getOrCreate(SparkContext.scala:2480)
at org.apache.spark.sql.SparkSession$Builder.$anonfun$getOrCreate$5(SparkSession.scala:948)
at scala.Option.getOrElse(Option.scala:121)
at org.apache.spark.sql.SparkSession$Builder.getOrCreate(SparkSession.scala:939)
at org.apache.spark.mllib.util.MLlibTestSparkContext.beforeAll(MLlibTestSparkContext.scala:38)
at org.apache.spark.mllib.util.MLlibTestSparkContext.beforeAll$(MLlibTestSparkContext.scala:34)
at org.apache.spark.mllib.optimization.GradientDescentSuite.beforeAll(GradientDescentSuite.scala:65)
at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:212)
at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
at org.apache.spark.SparkFunSuite.run(SparkFunSuite.scala:52)
at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:314)
at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:507)
at sbt.ForkMain$Run$2.call(ForkMain.java:296)
at sbt.ForkMain$Run$2.call(ForkMain.java:286)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)