[viraptor]

> after application restart and continue from there.

What if the application doesn't restart before the queue decides the message was lost and resends?

[hashhar]

In Kafka the "queue" is dumb, it doesn't lose messages (it's an append only durable log) nor does it resend anything unless the consumer requests it.

[viraptor]

There has to be a retry system somewhere, otherwise you'd end up with a 0-or-more delivery system if the app crashes after picking up from the queue, but never processing or ack-ing.