//inputDataFrame
+---+------+----------+
|age|  name|occupation|
+---+------+----------+
| []|Harish| developer|
+---+------+----------+

df.withColumn("age",explode(col("age")))

//DataFrame with age column exploded
+---+----+----------+
|age|name|occupation|
+---+----+----------+
+---+----+----------+

// expected DataFrame
    +---+------+----------+     +----+------+----------+
    |age|  name|occupation|     |age |  name|occupation|
    +---+------+----------+ (or)+----+------+----------+
    |   |Harish| developer|     |null|Harish| developer|
    +---+------+----------+     +----+------+----------+