Github user GJL commented on a diff in the pull request:
https://github.com/apache/flink/pull/4915#discussion_r147442314
--- Diff:
flink-connectors/flink-connector-kafka-0.11/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaProducer011.java
---
@@ -563,7 +553,7 @@ public void close() throws Exception {
asyncException = ExceptionUtils.firstOrSuppressed(e,
asyncException);
}
try {
- producersPool.close();
+ producersPool.ifPresent(pool -> pool.close());
--- End diff --
I am not adamant about it but using `Optional` in private fields is not
without controversy: https://stackoverflow.com/a/26328555
Also, `ifPresent(pool -> pool.close()` only works because `close` does not
declare any checked exceptions. If it did, the code would not compile.
---
