Spark UDF exception when accessing broadcast variable

I'm having difficulty accessing a scala.collection.immutable.Map from inside a spark UDF.

I'm broadcasting the map

val browserLangMap = sc.broadcast (Source.fromFile(browserLangFilePath).getLines.map(_.split(,)).map(e => (e(0).toInt,e(1))).toMap)

creating UDF that access the map

def addBrowserCode = udf((browserLang:Int) => if(browserLangMap.value.contains(browserLang)) browserLangMap.value(browserLang) else "")`

using the UDF to add new column

val joinedDF = rawDF.join(broadcast(geoDF).as("GEO"), $"start_ip" === $"GEO.start_ip_num", "left_outer")
                        .withColumn("browser_code", addBrowserCode($"browser_language"))
                        .selectExpr(getSelectQuery:_*)

full stack trace --> https://www.dropbox.com/s/p1d5322fo9cxro6/stack_trace.txt?dl=0

org.apache.spark.SparkException: Task not serializable
        at org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:304)
        at org.apache.spark.util.ClosureCleaner$.org$apache$spark$util$ClosureCleaner$$clean(ClosureCleaner.scala:294)
        at org.apache.spark.util.ClosureCleaner$.clean(ClosureCleaner.scala:122)
        at org.apache.spark.SparkContext.clean(SparkContext.scala:2055)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:1857)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.io.NotSerializableException: $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$MetaDataSchema$
Serialization stack:
        - object not serializable (class: $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$MetaDataSchema$, value: $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$MetaDataSchema$@30b4ba52)
        - field (class: $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC, name: MetaDataSchema$module, type: class $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$MetaDataSchema$)
        - object (class org.apache.spark.sql.catalyst.expressions.ScalaUDF, UDF(browser_language#235))
        - field (class: org.apache.spark.sql.catalyst.expressions.If, name: falseValue, type: class org.apache.spark.sql.catalyst.expressions.Expression)
        - object (class org.apache.spark.sql.catalyst.expressions.If, if (isnull(browser_language#235)) null else UDF(browser_language#235))
        - field (class: org.apache.spark.sql.catalyst.expressions.Alias, name: child, type: class org.apache.spark.sql.catalyst.expressions.Expression)
        - object (class org.apache.spark.sql.catalyst.expressions.Alias, if (isnull(browser_language#235)) null else UDF(browser_language#235) AS browser_language#507)
        - object (class org.apache.spark.OneToOneDependency, org.apache.spark.OneToOneDependency@5ae38c4e)
        - writeObject data (class: scala.collection.immutable.$colon$colon)
        - object (class scala.collection.immutable.$colon$colon, List(org.apache.spark.OneToOneDependency@5ae38c4e))
        - field (class: org.apache.spark.rdd.RDD, name: org$apache$spark$rdd$RDD$$dependencies_, type: interface scala.collection.Seq)
        at org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:301)
        ... 80 more

I know its the access to broadcast Map that is causing this. When I remove reference to that in the UDF there are no exception.

def addBrowserCode = udf((browserLang:Int) => browserLang.toString())  //Test UDF without accessing broadcast Map and it works

Spark version 1.6

I found this to be a strange behavior with ":paste" in spark shell. This happens only when I paste my entire code in a single multi-line paste with :paste.

The same code works perfectly if I paste the broadcast and UDF creation first and then paste the join+saveToFile in a separate :paste.

May be scala shell issue. I don't know.