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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_PERSISTENTThis is the lowest-overhead delivery mode because it does not require that the message be logged to stable storage. | 
| static int | PERSISTENTThis delivery mode instructs the JMS provider to log the message to stable storage as part of the client's send operation. | 
| Field Detail | 
public static final int NON_PERSISTENT
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.
public static final int PERSISTENT
PERSISTENT message to be lost.
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Copyright 2003 Sun Microsystems, Inc. All rights reserved.