User defined functions in Scala cannot be applied

Related to stackoverflow question http://stackoverflow.com/questions/39857803/class-not-found-when-applying-udf-in-apache-zeppelin
and issue ZEPPELIN-150

Applying an UDF in the scala interpreter generates a class not found exception.

The following code works as expected in spark-shell (both 1.6.0 and 2.0.0) and can be used to reproduce the issue in Zeppelin 0.6.0:

import org.apache.spark.sql.functions._
val data = sqlContext.read.json(sc.parallelize(Seq("

{'location' : 'london'}

", "

{'location': 'tokyo'}

")))
val cities = Seq("london", "paris")
val urbf = udf

{ city: String => if (cities.contains(city)) 1 else 0 }

sqlc.udf.register("sentiment", sentiment _)
data.select($"location", urbf($"location")).show

The error is:
java.lang.ClassNotFoundException: $iwC$$iwC$$iwC$$iwC$$iwC$$$$cd8ca64e19a07f9732e2b3de5fd5fc88$$$$$iwC$$iwC$$iwC$$iwC$$anonfun$1