I am adding two JMS messages in the same destination sequentially. Will both of these messages be received in the same order in which I have added them or is there a chance for reverse ordering, that is, which ever the message is received first in the destination will be retrieved first.
I am adding into a destination as:
producer.send(Msg1);
producer.send(Msg2);
Msg1 and Msg2 will be added sequentially in all the cases (like network failures and latency. etc.)?
Message ordering is not guaranteed (and not mandated by the specification) and Total JMS Message ordering explains the details of why. Also see the Stack Overflow post How to handle order of messages in JMS?.
As per JMS2 specs
JMS defines that messages sent by a session to a destination must be received
in the order in which they were sent. This defines a partial ordering
constraint on a session’s input message stream.
JMS does not define order of message receipt across destinations or across
a destination’s messages sent from multiple sessions. This aspect of a
session’s input message stream order is timing-dependent. It is not under
application control.
Also
Although clients loosely view the messages they produce within a session
as forming a serial stream of sent messages, the total ordering of this stream
is not significant. The only ordering that is visible to receiving clients is
the order of messages a session sends to a particular destination.
Several things can affect this order like message priority,
persistent/non persistent etc.
So to answer your question messages will be received in the same order they were sent with above information. The order in which messages are delivered to the server however will be constrained by limitations like message priority, persistent/non persistent etc.
