javax.jms

## Interface DeliveryMode

-     public interface DeliveryMode

  The delivery modes supported by the JMS API are `PERSISTENT` and `NON_PERSISTENT`.

  A client marks a message as persistent if it feels that the application will have problems if the message is lost in transit. A client marks a message as non-persistent if an occasional lost message is tolerable. Clients use delivery mode to tell a JMS provider how to balance message transport reliability with throughput.

  Delivery mode covers only the transport of the message to its destination. Retention of a message at the destination until its receipt is acknowledged is not guaranteed by a `PERSISTENT` delivery mode. Clients should assume that message retention policies are set administratively. Message retention policy governs the reliability of message delivery from destination to message consumer. For example, if a client's message storage space is exhausted, some messages may be dropped in accordance with a site-specific message retention policy.

  A message is guaranteed to be delivered once and only once by a JMS provider if the delivery mode of the message is `PERSISTENT` and if the destination has a sufficient message retention policy.

  Since:
    JMS 1.0

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `NON_PERSISTENT` This is the lowest-overhead delivery mode because it does not require that the message be logged to stable storage.
    `static int` | `PERSISTENT` This delivery mode instructs the JMS provider to log the message to stable storage as part of the client's send operation.

- - ### Field Detail

    - #### NON_PERSISTENT

          static final int NON_PERSISTENT

      This is the lowest-overhead delivery mode because it does not require that the message be logged to stable storage. The level of JMS provider failure that causes a `NON_PERSISTENT` message to be lost is not defined.

      A JMS provider must deliver a `NON_PERSISTENT` message with an at-most-once guarantee. This means that it may lose the message, but it must not deliver it twice.

      See Also:
        Constant Field Values

    - #### PERSISTENT

          static final int PERSISTENT

      This delivery mode instructs the JMS provider to log the message to stable storage as part of the client's send operation. Only a hard media failure should cause a `PERSISTENT` message to be lost.
      See Also:
        Constant Field Values

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