ConcurrentModificationException in SimpleBrokerMessageHandler [SPR-12665]

[spring-projects-issues]

Piotr Leśniak opened SPR-12665 and commented

During invocation of SimpMessageSendingOperations::convertAndSend method ConcurrentModificationException occures. It happens very rarely (I found out about this bug by checking logs from production, I haven't seen it in application), probably when invocation of this method happens simultaneously with closing webSocket on a client.

Here's a stack:

org.springframework.messaging.MessageDeliveryException: Failed to handle message to ExecutorSubscribableChannel[brokerChannel] in SimpleBroker[DefaultSubscriptionRegistry[cache[2 destination(s)], registry[2 sessions]]]; nested exception is java.util.ConcurrentModificationException
	at org.springframework.messaging.support.ExecutorSubscribableChannel$SendTask.run(ExecutorSubscribableChannel.java:180) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.support.ExecutorSubscribableChannel.sendInternal(ExecutorSubscribableChannel.java:93) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.support.AbstractMessageChannel.send(AbstractMessageChannel.java:107) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.support.AbstractMessageChannel.send(AbstractMessageChannel.java:94) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.simp.SimpMessagingTemplate.sendInternal(SimpMessagingTemplate.java:185) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.simp.SimpMessagingTemplate.doSend(SimpMessagingTemplate.java:160) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.simp.SimpMessagingTemplate.doSend(SimpMessagingTemplate.java:47) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:95) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:133) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:113) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:108) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at 
.... [our application stack leading to convertAndSend on SimpMessageSendingOperations object]
Caused by: java.util.ConcurrentModificationException: null
	at java.util.LinkedHashMap$LinkedHashIterator.nextEntry(LinkedHashMap.java:394) ~[na:1.7.0_55]
	at java.util.LinkedHashMap$KeyIterator.next(LinkedHashMap.java:405) ~[na:1.7.0_55]
	at org.springframework.messaging.simp.broker.SimpleBrokerMessageHandler.sendMessageToSubscribers(SimpleBrokerMessageHandler.java:227) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.simp.broker.SimpleBrokerMessageHandler.handleMessageInternal(SimpleBrokerMessageHandler.java:183) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.handleMessage(AbstractBrokerMessageHandler.java:180) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	at org.springframework.messaging.support.ExecutorSubscribableChannel$SendTask.run(ExecutorSubscribableChannel.java:172) ~[spring-messaging-4.1.0.RELEASE.jar:4.1.0.RELEASE]
	... 24 common frames omitted

Can it be related to this #16377 bug?

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Affects: 4.1 GA

Issue Links:

• ConcurrentModificationException when calling SimpMessagingTemplate.convertAndSend [SPR-13185] #17777 ConcurrentModificationException when calling SimpMessagingTemplate.convertAndSend

[spring-projects-issues]

Rossen Stoyanchev commented

Although DefaultSubscriptionRegistry maintained separate "update" and "access" caches to ensure that findSubscriptions returns a safe to iterate map, there was a bug in the addSubscriptions method that mistakenly used the original map for the "update" cache. This has been fixed.