[GitHub] [spark] srowen commented on a change in pull request #31540: [SPARK-20977][CORE] Use a non-final field for the state of CollectionAccumulator

[GitBox <gi...@apache.org>]

srowen commented on a change in pull request #31540:
URL: https://github.com/apache/spark/pull/31540#discussion_r578541850



##########
File path: core/src/main/scala/org/apache/spark/util/AccumulatorV2.scala
##########
@@ -449,39 +449,46 @@ class DoubleAccumulator extends AccumulatorV2[jl.Double, jl.Double] {
  * @since 2.0.0
  */
 class CollectionAccumulator[T] extends AccumulatorV2[T, java.util.List[T]] {
-  private val _list: java.util.List[T] = Collections.synchronizedList(new ArrayList[T]())
+  private var _list: java.util.List[T] = _

Review comment:
       Does a `lazy val` work here? not sure what it generates under the hood or whether it would also fix the issue. It would be simpler than handling init lazily, but this is no big deal.




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org