apache spark - WrappedArray of WrapedArray to java array -

i have column of type set , use collect_set() of spark dataset api returns wrapped array of wrapped array. want single array values of nested wrapped arrays. how can that?

eg. cassandra table:

col1   {1,2,3} {1,5} 

i'm using spark dataset api.
row.get(0) returns wrapped array of wrapped array.

consider have dataset<row> ds has value column.

+-----------------------+ |value                  | +-----------------------+ |[wrappedarray(1, 2, 3)]| +-----------------------+ 

and has below schema

root  |-- value: array (nullable = true)  |    |-- element: array (containsnull = true)  |    |    |-- element: integer (containsnull = false) 

using udf

define udf1 below.

static udf1<wrappedarray<wrappedarray<integer>>, list<integer>> getvalue = new udf1<wrappedarray<wrappedarray<integer>>, list<integer>>() {       public list<integer> call(wrappedarray<wrappedarray<integer>> data) throws exception {         list<integer> intlist = new arraylist<integer>();         for(int i=0; i<data.size(); i++){             intlist.addall(javaconversions.seqasjavalist(data.apply(i)));         }         return intlist;     } }; 

register , call udf1 below

import static org.apache.spark.sql.functions.col; import static org.apache.spark.sql.functions.calludf; import scala.collection.javaconversions;  //register udf spark.udf().register("getvalue", getvalue, datatypes.createarraytype(datatypes.integertype));  //call udf dataset<row> ds1  = ds.select(col("*"), calludf("getvalue", col("value")).as("udf-value")); ds1.show(); 

using explode function

import static org.apache.spark.sql.functions.col; import static org.apache.spark.sql.functions.explode;  dataset<row> ds2 = ds.select(explode(col("value")).as("explode-value")); ds2.show(false);