The Java client sets the message delivery property 'timestamp' when it publishes a message. This is inconsistent with the AMQP 0-10 definition of this field:
"The timestamp is set by the broker on arrival of the message."
The Java client uses this property to implement the JMSTimestamp property as defined by the JMS spec, which is defined as the time the message is
The Broker now implements the timestamp feature as defined in 0.10, which means it will overwrite the value set by the Java client.
A possible solution would be to have the Java client introduce its own custom property to represent the JMS timestamp, and not use the AMQP delivery property header.