DefaultSplitter and java.util.ConcurrentModificationException

[snc85]

Ok. THANK YOU GUYS!!!

[Gary Russell]

Just to be clear; this code...

for (IData data : dataList) {

is iterating over dataList(). The exception is caused because dataList is being modified after the interator is created. This might be another thread; it might be the current thread.

When using this Java5 syntax, you are NOT allowed to modify the list (e.g. remove an element) within the loop. If you need to do that, you need to explicitly use an iterator, and use the iterator to remove the item...

Iterator<IData> iterator = dataList.iterator();
while (iterator.hasNext) {
    IData iData = iterator.next();
...
    iterator.remove();
}

If you are not removing elements in the loop, then some other thread must be modifying the list.

[snc85]

No, no...no removing from list
To sum up, now I have such components as:
- udp-inbound-channel-adapter
- transformer
- filter
- resequencer
- logging-channel-adapter

	<int-ip:udp-inbound-channel-adapter
		id="udpInput" channel="inputChannel" multicast="true"
		multicast-address="230.0.0.1" port="4446" receive-buffer-size="1400" />
	<int:channel id="inputChannel" />

	<int:chain id="headerChain" input-channel="inputChannel"
		output-channel="headerTransformedChannel">
		<int:transformer ref="headerTransformer" />
		<int:header-enricher>
			<int:header name="correlationId" expression="payload.header.serviceID"
				overwrite="true" />
			<int:header name="sequenceNumber" expression="payload.header.packetSeqNum"
				overwrite="true" />
		</int:header-enricher>
	</int:chain>
	<int:channel id="headerTransformedChannel">
		<int:interceptors>
			<int:wire-tap channel="packetControlChannel" />
		</int:interceptors>
	</int:channel>

	<int:filter input-channel="headerTransformedChannel"
		discard-channel="packetTypeErrorChannel" output-channel="packetFilteredChannel"
		ref="packetTypeFilter" />
	<int:channel id="packetFilteredChannel" />
	
	<int:resequencer id="seqNumberResequencer" comparator="messageComparator"
		input-channel="packetFilteredChannel" output-channel="logger"
		release-strategy="sequenceReleaseStrategy" />

	<int:logging-channel-adapter id="logger" expression="payload.header.packetSeqNum" />

And I am getting:

Exception in thread "UDP-Incoming-Msg-Handler" org.springframework.integration.MessageHandlingException: error occurred in message handler [org.springframework.integration.aggregator.CorrelatingMessageHandler#0]
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:84)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:110)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:97)
	at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:61)
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:157)
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:128)
	at org.springframework.integration.core.MessagingTemplate.doSend(MessagingTemplate.java:288)
	at org.springframework.integration.core.MessagingTemplate.send(MessagingTemplate.java:149)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendMessage(AbstractReplyProducingMessageHandler.java:176)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendReplyMessage(AbstractReplyProducingMessageHandler.java:160)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.produceReply(AbstractReplyProducingMessageHandler.java:125)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleResult(AbstractReplyProducingMessageHandler.java:119)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:101)
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:78)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:110)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:97)
	at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:61)
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:157)
	at org.springframework.integration.handler.MessageHandlerChain$ReplyForwardingMessageChannel.send(MessageHandlerChain.java:210)
	at org.springframework.integration.handler.MessageHandlerChain$ReplyForwardingMessageChannel.send(MessageHandlerChain.java:203)
	at org.springframework.integration.core.MessagingTemplate.doSend(MessagingTemplate.java:288)
	at org.springframework.integration.core.MessagingTemplate.send(MessagingTemplate.java:149)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendMessage(AbstractReplyProducingMessageHandler.java:176)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendReplyMessage(AbstractReplyProducingMessageHandler.java:160)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.produceReply(AbstractReplyProducingMessageHandler.java:125)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleResult(AbstractReplyProducingMessageHandler.java:119)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:101)
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:78)
	at org.springframework.integration.handler.MessageHandlerChain$1.send(MessageHandlerChain.java:154)
	at org.springframework.integration.core.MessagingTemplate.doSend(MessagingTemplate.java:288)
	at org.springframework.integration.core.MessagingTemplate.send(MessagingTemplate.java:149)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendMessage(AbstractReplyProducingMessageHandler.java:176)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.sendReplyMessage(AbstractReplyProducingMessageHandler.java:160)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.produceReply(AbstractReplyProducingMessageHandler.java:125)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleResult(AbstractReplyProducingMessageHandler.java:119)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:101)
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:78)
	at org.springframework.integration.handler.MessageHandlerChain.handleMessageInternal(MessageHandlerChain.java:137)
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:78)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:110)
	at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:97)
	at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:61)
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:157)
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:128)
	at org.springframework.integration.core.MessagingTemplate.doSend(MessagingTemplate.java:288)
	at org.springframework.integration.core.MessagingTemplate.send(MessagingTemplate.java:149)
	at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:92)
	at org.springframework.integration.ip.udp.UnicastReceivingChannelAdapter.access$300(UnicastReceivingChannelAdapter.java:43)
	at org.springframework.integration.ip.udp.UnicastReceivingChannelAdapter$1.run(UnicastReceivingChannelAdapter.java:151)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
	at org.springframework.integration.aggregator.CorrelatingMessageHandler.handleMessageInternal(CorrelatingMessageHandler.java:169)
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:78)
	... 51 more