JMS queue A staging area that contains messages that have been sent and are waiting to be read. Note that, contrary to what the name queue suggests, messages don't have to be delivered in the order sent. A JMS queue only guarantees that each message is processed only once. Incorrect: Not B: (Only one queue required) *A distributed destination is a set of destinations (queues or topics) that are accessible as a single, logical destination to a client. A distributed destination has the following characteristics: It is referenced by its own JNDI name. Members of the set are usually distributed across multiple servers within a cluster, with each destination member belonging to a separate JMS server. *A distributed queue is a set of physical JMS queue members. As such, a distributed queue can be used to create a QueueSender, QueueReceiver, and a QueueBrowser. The fact that a distributed queue represents multiple physical queues is mostly transparent to your application. Not Topic: JMS topic A distribution mechanism for publishing messages that are delivered to multiple subscribers.