lbradstreet opened a new pull request #10704: URL: https://github.com/apache/kafka/pull/10704
Recently we have noticed multiple instances where KafkaProducers have failed to constructer due to the following exception: ``` org.apache.kafka.common.KafkaException: Failed to construct kafka producer at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:440) at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:291) at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:318) java.base/java.lang.Thread.run(Thread.java:832) Caused by: java.util.ConcurrentModificationException at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1584) at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1607) at java.base/java.util.AbstractSet.removeAll(AbstractSet.java:171) at org.apache.kafka.common.config.AbstractConfig.unused(AbstractConfig.java:221) at org.apache.kafka.common.config.AbstractConfig.logUnused(AbstractConfig.java:379) at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:433) ... 9 more exception.class:org.apache.kafka.common.KafkaException exception.message:Failed to construct kafka producer ``` This is due to the fact that `used` below is a synchronized set. `used` is being modified while removeAll is being called. This may be due to the way that keys are added to it when used. Switching to a CopyOnWriteArraySet avoids this issue as it support concurrent iteration. -- 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: us...@infra.apache.org
