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## 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.

Field Summary
`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

    public 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

    public 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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