Spark java.lang.ClassCastException: scala.collection.mutable.WrappedArray$ofRef cannot be cast to java.util.ArrayList

Resolved the error by converting to Seq(Sequence Type)

Earlier :

val bufferMap: Map[Int, util.ArrayList[String]] = buffer.getAs[Map[Int, util.ArrayList[String]]](1)

Modified :

val bufferMap: Map[Int, Seq[String]] = buffer.getAs[Map[Int, Seq[String]]](1)