Queues provide the facility for users to store messages in an intermediate location sent by an external party, and access them on-demand. WSO2 Message Broker uses a Message Queue to facilitate this feature, and all operations are carried out on that message queue. The queuing feature is similar to an inbox where anyone can send messages to and only the owner can consume the messages. While anyone can send messages to the queue, only the owner of the queue can access the messages stored in it.
The message queue architecture is depicted in the figure below.
Figure: How Message Queues Work