Requirement: session.DUPS_OK_ACKNOWLEDGE

With the DUPS_OK_ACKNOWLEDGE session acknowledgement mode, the session lazily acknowledges the delivery of messages. This is likely to result in the delivery of some duplicate messages if JMS fails, so it should be used only by consumers that are tolerant of duplicate messages. Its benefit is the reduction of session overhead achieved by minimizing the work the session does to prevent duplicates.

See:

• Section 4.4.11, Message Acknowledgment