Abstract: A method of operating a message handling system comprises maintaining queues, receiving messages, placing each message on a queue, running one or more applications which access the queues, detecting the receipt of a message with a predefined flag, and blocking at least one application from accessing the message with the predefined flag. The blocking of at least one application from accessing the message with the predefined flag can be achieved by discarding the message with the predefined flag prior to the message being placed on a queue. In an alternative embodiment, the blocking is achieved by preventing the blocked applications from removing the message from a queue.

Abstract: A system and method for messaging in which, when a connection to a queue manager (220) is established, the queue manager allocates a Connection Identifier from the same name space (300) as Message Identifiers and returns this information (400) to the user. The user can then use this Connection Identifier as a Correlation Identifier, safe in the knowledge that it will not clash with any system generated Message Identifier or Correlation Identifier. A secondary benefit to this allocation scheme is that if a shared reply queue suffers from a build-up of messages then the Correlation Identifier in those messages can be used to identify the application expected to receive those messages.