Hello, I'm trying to run the following example code:
import org.apache.spark.sql.hive.HiveContext import org.apache.spark.{SparkContext, SparkConf} import org.apache.spark.sql.functions._ case class RecordExample(a: Int, b: String) object ArrayExample { def main(args: Array[String]) { val conf = new SparkConf() val sc = new SparkContext(conf) val sqlContext = new HiveContext(sc) import sqlContext.implicits._ val dataset = sc.parallelize(Seq(RecordExample(1, "apple"), RecordExample(2, "orange"))).toDS() dataset.groupBy($"a").agg(collect_list("b").as[List[String]]) dataset.collect() } } and it fails with the following (please see the whole stack trace below): Exception in thread "main" java.lang.ClassCastException: org.apache.spark.sql.types.ArrayType cannot be cast to org.apache.spark.sql.types.StructType Could please someone point me to the proper way to do that or confirm it's a bug? Thank you and here is the whole stacktrace: Exception in thread "main" java.lang.ClassCastException: org.apache.spark.sql.types.ArrayType cannot be cast to org.apache.spark.sql.types.StructType at org.apache.spark.sql.catalyst.expressions.GetStructField.org $apache$spark$sql$catalyst$expressions$GetStructField$$field$lzycompute(complexTypeExtractors.scala:107) at org.apache.spark.sql.catalyst.expressions.GetStructField.org $apache$spark$sql$catalyst$expressions$GetStructField$$field(complexTypeExtractors.scala:107) at org.apache.spark.sql.catalyst.expressions.GetStructField.dataType(complexTypeExtractors.scala:109) at org.apache.spark.sql.catalyst.analysis.ResolveUpCast$$anonfun$apply$24.applyOrElse(Analyzer.scala:1214) at org.apache.spark.sql.catalyst.analysis.ResolveUpCast$$anonfun$apply$24.applyOrElse(Analyzer.scala:1211) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:243) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:243) at org.apache.spark.sql.catalyst.trees.CurrentOrigin$.withOrigin(TreeNode.scala:53) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:242) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4.apply(TreeNode.scala:265) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.trees.TreeNode.transformChildren(TreeNode.scala:305) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4.apply(TreeNode.scala:265) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.trees.TreeNode.transformChildren(TreeNode.scala:305) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4$$anonfun$apply$9.apply(TreeNode.scala:294) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.immutable.List.foreach(List.scala:381) at scala.collection.TraversableLike$class.map(TraversableLike.scala:245) at scala.collection.immutable.List.map(List.scala:285) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4.apply(TreeNode.scala:292) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.trees.TreeNode.transformChildren(TreeNode.scala:305) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4$$anonfun$apply$9.apply(TreeNode.scala:294) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48) at scala.collection.TraversableLike$class.map(TraversableLike.scala:245) at scala.collection.AbstractTraversable.map(Traversable.scala:104) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4.apply(TreeNode.scala:292) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.trees.TreeNode.transformChildren(TreeNode.scala:305) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformDown$1.apply(TreeNode.scala:248) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$4.apply(TreeNode.scala:265) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.trees.TreeNode.transformChildren(TreeNode.scala:305) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:248) at org.apache.spark.sql.catalyst.plans.QueryPlan.transformExpressionDown$1(QueryPlan.scala:75) at org.apache.spark.sql.catalyst.plans.QueryPlan.org $apache$spark$sql$catalyst$plans$QueryPlan$$recursiveTransform$1(QueryPlan.scala:85) at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$org$apache$spark$sql$catalyst$plans$QueryPlan$$recursiveTransform$1$1.apply(QueryPlan.scala:89) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245) at scala.collection.immutable.List.foreach(List.scala:381) at scala.collection.TraversableLike$class.map(TraversableLike.scala:245) at scala.collection.immutable.List.map(List.scala:285) at org.apache.spark.sql.catalyst.plans.QueryPlan.org $apache$spark$sql$catalyst$plans$QueryPlan$$recursiveTransform$1(QueryPlan.scala:89) at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$1.apply(QueryPlan.scala:93) at scala.collection.Iterator$$anon$11.next(Iterator.scala:370) at scala.collection.Iterator$class.foreach(Iterator.scala:742) at scala.collection.AbstractIterator.foreach(Iterator.scala:1194) at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:104) at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:48) at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:308) at scala.collection.AbstractIterator.to(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:300) at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1194) at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:287) at scala.collection.AbstractIterator.toArray(Iterator.scala:1194) at org.apache.spark.sql.catalyst.plans.QueryPlan.transformExpressionsDown(QueryPlan.scala:93) at org.apache.spark.sql.catalyst.plans.QueryPlan.transformExpressions(QueryPlan.scala:64) at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$transformAllExpressions$1.applyOrElse(QueryPlan.scala:134) at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$transformAllExpressions$1.applyOrElse(QueryPlan.scala:133) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:243) at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$3.apply(TreeNode.scala:243) at org.apache.spark.sql.catalyst.trees.CurrentOrigin$.withOrigin(TreeNode.scala:53) at org.apache.spark.sql.catalyst.trees.TreeNode.transformDown(TreeNode.scala:242) at org.apache.spark.sql.catalyst.trees.TreeNode.transform(TreeNode.scala:233) at org.apache.spark.sql.catalyst.plans.QueryPlan.transformAllExpressions(QueryPlan.scala:133) at org.apache.spark.sql.catalyst.analysis.ResolveUpCast$.apply(Analyzer.scala:1211) at org.apache.spark.sql.catalyst.analysis.ResolveUpCast$.apply(Analyzer.scala:1195) at org.apache.spark.sql.catalyst.rules.RuleExecutor$$anonfun$execute$1$$anonfun$apply$1.apply(RuleExecutor.scala:83) at org.apache.spark.sql.catalyst.rules.RuleExecutor$$anonfun$execute$1$$anonfun$apply$1.apply(RuleExecutor.scala:80) at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:124) at scala.collection.immutable.List.foldLeft(List.scala:84) at org.apache.spark.sql.catalyst.rules.RuleExecutor$$anonfun$execute$1.apply(RuleExecutor.scala:80) at org.apache.spark.sql.catalyst.rules.RuleExecutor$$anonfun$execute$1.apply(RuleExecutor.scala:72) at scala.collection.immutable.List.foreach(List.scala:381) at org.apache.spark.sql.catalyst.rules.RuleExecutor.execute(RuleExecutor.scala:72) at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder.resolve(ExpressionEncoder.scala:253) at org.apache.spark.sql.Dataset.<init>(Dataset.scala:78) at org.apache.spark.sql.GroupedDataset.aggUntyped(GroupedDataset.scala:240) at org.apache.spark.sql.GroupedDataset.agg(GroupedDataset.scala:253) at ArrayExample$.main(ArrayExample.scala:22) at ArrayExample.main(ArrayExample.scala) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:731) at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:181) at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:206) at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:121) at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)