ConcurrentModificationException in Kafka Producer 2.1.0

[Mark Anderson]

Hi,

I'm periodically seeing ConcurrentModificationExceptions in the producer
when records are expired e.g.

ERROR Dec 05 11:56:13.033 388753 [kafka-producer-network-thread |
analogDataProducer] com.x.AnalogMessageBundler Exception
org.apache.kafka.common.errors.TimeoutException:
 Expiring 1 record(s) for topic-3:1021 ms has passed since batch creation
ERROR Dec 05 11:56:13.038 388758 [kafka-producer-network-thread |
analogDataProducer] org.apache.kafka.clients.producer.internals.Sender
[Producer clientId=analogDataProducer] Uncaught error
 in kafka producer I/O thread:
java.util.ConcurrentModificationException
      at java.util.HashMap$HashIterator.nextNode(HashMap.java:1442)
        at java.util.HashMap$EntryIterator.next(HashMap.java:1476)
            at java.util.HashMap$EntryIterator.next(HashMap.java:1474)
                 at
org.apache.kafka.clients.producer.internals.Sender.getExpiredInflightBatches(Sender.java:177)
                      at
org.apache.kafka.clients.producer.internals.Sender.sendProducerData(Sender.java:353)
                              at
org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:308)
                                   at
org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:233)
                                        at
java.lang.Thread.run(Thread.java:748)

Note that I'm continually calling send on the producer (approx 15k
calls/second). Previously I've been using 1.1.1 clients and haven't seen
this issue.

Please let me know if there is any more information I can supply.

Thanks,
Mark