GH-3726: Avoid ConcurrentModificationException in KafkaMessageListenerContainer #3728
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Fixes possible
ConcurrentModificationException
inKafkaMessageListenerContainer
that can happen in case if any ofpartitionsListenerConsumer.definedPartitions
orpartitionsListenerConsumer.assignedPartitions
fields are being iterated/modified simultaneously.For instance by consumer thread performing rebalancing and arbitrary application thread calling
getAssignedPartitions
method inKafkaMessageListenerContainer
.To achieve desired effect I'm using synchronized wrappers. I would prefer modern concurrent collections such as
ConcurrentHashMap
, butdefinedPartitions
field has type ofLinkedHashMap
and itskeySet
preserves keys order.Thus 1) no thread safe data structures available from std lib with same characteristics 2) possibly some users rely on the order. Anyway do not think that there are real life cases that can put
definedPartitions
orassignedPartitions
under pressure.Fixes GH-3726 (#3726)