What mechanisms ensure message delivery reliability in queues using JMS protocol?

The following mechanisms are used to ensure reliable message delivery in JMS:

• Transactions: guarantee that a message will be delivered and processed completely or not at all.
• Acknowledgements: the client confirms receipt of a message, allowing the broker to remove it from the queue.
• Message persistence: messages are stored on disk to prevent loss in case of broker failure.
• Delivery modes:
  • Persistent — guarantees delivery even in case of failures.
  • Non-persistent — faster, but without delivery guarantees.
• Dead Letter Queue (DLQ): a queue for messages that could not be delivered after several attempts.

These mechanisms together ensure reliable and guaranteed message delivery in JMS systems.