мне кажется тоже речь про какие то более мудреные случаи:
scala> spark.range(1).select(lit(null).alias("foo")).as[Foo].show
+----+
| foo|
+----+
|null|
+----+
scala> spark.range(1).select(lit(null).alias("foo")).as[Foo].collect
java.lang.NullPointerException: Null value appeared in non-nullable field:
- field (class: "scala.Int", name: "foo")
- root class: "Foo"
If the schema is inferred from a Scala tuple/case class, or a Java bean, please try to use scala.Option[_] or other nullable types (e.g. java.lang.Integer instead of int/scala.Int).