UDAF "not found: type UserDefinedAggregateFunction" in zeppelin 0.6.2

[Manjunath, Kiran]

I am trying the below sample code

Code

%spark
import org.apache.spark.sql.expressions.MutableAggregationBuffer
import org.apache.spark.sql.expressions.UserDefinedAggregateFunction


class GeometricMean extends UserDefinedAggregateFunction {
  def inputSchema: org.apache.spark.sql.types.StructType =
    StructType(StructField("value", DoubleType) :: Nil)
  def bufferSchema: StructType = StructType(
    StructField("count", LongType) ::
    StructField("product", DoubleType) :: Nil
  )
  def dataType: DataType = DoubleType
  def deterministic: Boolean = true
  def initialize(buffer: MutableAggregationBuffer): Unit = {
    buffer(0) = 0L
    buffer(1) = 1.0
  }
  def update(buffer: MutableAggregationBuffer,input: Row): Unit = {
    buffer(0) = buffer.getAs[Long](0) + 1
    buffer(1) = buffer.getAs[Double](1) * input.getAs[Double](0)
  }
  def merge(buffer1: MutableAggregationBuffer, buffer2: Row): Unit = {
    buffer1(0) = buffer1.getAs[Long](0) + buffer2.getAs[Long](0)
    buffer1(1) = buffer1.getAs[Double](1) * buffer2.getAs[Double](1)
  }
  def evaluate(buffer: Row): Any = {
    math.pow(buffer.getDouble(1), 1.toDouble / buffer.getLong(0))
  }
}


Error

import org.apache.spark.sql.expressions.MutableAggregationBuffer
import org.apache.spark.sql.expressions.UserDefinedAggregateFunction
<console>:11: error: not found: type UserDefinedAggregateFunction
class GeometricMean extends UserDefinedAggregateFunction {
^


Is this a known problem?
Any workaround for this?

Regards,
Kiran