java.lang.UnsupportedOperationException: MessageHeaders is immutable if I add header in the handler

Question

I have following line in my handler:

headers.put(EMPTY_FILE, true);

It is a reason of:

2019-11-26 13:36:29.420 ERROR 2216 --- [sub-subscriber3] o.s.integration.handler.LoggingHandler   : ErrorMessage [payload=org.springframework.messaging.MessageHandlingException: error occurred during processing message in 'MethodInvokingMessageProcessor' [org.springframework.integration.handler.MethodInvokingMessageProcessor@319058ce]; nested exception is java.lang.UnsupportedOperationException: MessageHeaders is immutable, failedMessage=GenericMessage...

How could I fix it ?

Answer 1

MessageHeaders is read-only. You can only copy exists headers to new map (include your own header too) and create NEW MessageHeader from this map.