METHODS SYSTEMS AND COMPUTER PROGRAM PRODUCTS FOR SYNCHRONIZATION OF QUEUE-TO-QUEUE COMMUNICATIONS

Methods, systems, and computer program products are provided for communicating between a source device and a destination device over an external communication link by transmitting a message stored in a source persistent queue at the source device over the external communication link to the destination device. The transmitted message has transmitted with it an associated sequence identifier which identifies the message stored in the source persistent queue. The transmitted message and the associated sequence identifier are received at the destination device and stored in a destination persistent queue at the destination device. Occasionally, a commit message is transmitted to the source device from the destination device which identifies a sequence identifier associated with received message which has been persistently stored in the destination persistent queue. The persistently stored message in the destination persistent queue is made available to users of the destination device independent of whether a commit message identifying the message has been transmitted to the source device.