Camel and Spring's JmsTemplate and MessagListenerContainer.
Connections, sessions and producers are returned to a pool after use so that they can be reused later
without having to undergo the cost of creating them again.
b>NOTE: while this implementation does allow the creation of a collection of active consumers,
it does not 'pool' consumers. Pooling makes sense for connections, sessions and producers, which
are expensive to create and can remain idle a minimal cost. Consumers, on the other hand, are usually
just created at startup and left active, handling incoming messages as they come. When a consumer is
complete, it is best to close it rather than return it to a pool for later reuse: this is because,
even if a consumer is idle, ActiveMQ will keep delivering messages to the consumer's prefetch buffer,
where they'll get held until the consumer is active again.
If you are creating a collection of consumers (for example, for multi-threaded message consumption), you
might want to consider using a lower prefetch value for each consumer (e.g. 10 or 20), to ensure that
all messages don't end up going to just one of the consumers. See this FAQ entry for more detail:
http://activemq.apache.org/i-do-not-receive-messages-in-my-second-consumer.html
]]>