you should rollback to ensure the message is redelivered.
so I should do No.4:session.rollback()?, not No.3 message.acknowledge() and session.rollback()?
do I need to have persist-delivery-count-before-delivery>true</persist-delivery-count-before-delivery> in order to see DeliveryCount increase? I believe I did No.4 before yet the DeliveryCount still remains.
I will try again and update.
after I tried, I believe we need to do message.acknowledge() and session.rollbac(tru);