address comments

Author: cloud-fan

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/ScalaUDF.scala

@@ -1039,7 +1039,9 @@ case class ScalaUDF(
          try {
            $resultTerm = (${ctx.boxedType(dataType)})$catalystConverterTerm.apply($getFuncResult);
          } catch (NullPointerException e) {
-           throw new RuntimeException($scalaUDF.npeErrorMessage(), e);
+           NullPointerException npe = new NullPointerException($scalaUDF.npeErrorMessage());
+           npe.setStackTrace(e.getStackTrace());
+           throw npe;
          }
        """.stripMargin
 
@@ -1065,7 +1067,9 @@ case class ScalaUDF(
       f(input)
     } catch {
       case e: NullPointerException =>
-        throw new RuntimeException(npeErrorMessage, e)
+        val npe = new NullPointerException(npeErrorMessage)
+        npe.setStackTrace(e.getStackTrace)
+        throw npe
     }
 
     converter(result)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ScalaUDFSuite.scala

@@ -36,10 +36,10 @@ class ScalaUDFSuite extends SparkFunSuite with ExpressionEvalHelper {
       StringType,
       Literal.create(null, StringType) :: Nil)
 
-    val e1 = intercept[RuntimeException](udf.eval())
+    val e1 = intercept[NullPointerException](udf.eval())
     assert(e1.getMessage.contains("Given UDF throws NPE during execution"))
 
-    val e2 = intercept[RuntimeException] {
+    val e2 = intercept[NullPointerException] {
       checkEvalutionWithUnsafeProjection(udf, null)
     }
     assert(e2.getMessage.contains("Given UDF throws NPE during execution"))