Retry Advice and thread usage question

Quick question for someone with internals knowledge -

As an example, if I have a service activator that has stateless retry advice on it, and a retry might take a while (think very slow external service with back off retry) before we want to give up, is a thread used to wait for the retry, or is the message "parked" somewhere?

For example, if I had data coming in via JMS, and all other channels are direct, what would happen when I get stormed w/ 6 messages, all of which end up having to retry for a while?

JMS -> Inbound Channel adapter (poll, 5 threads) -> Transform -> Svc Activator (retry-advice) -> Outbound logging adapter.

The retry advice uses Spring Retry which suspends the thread during the back-off.

If you want to park the message and free up the thread, you can use an expression evaluating advice and send the message to a <delayer/> element instead. If you are worried about persistence during the parking, you can add a message store to the <delayer/>.

Thanks, Gary, exactly what I needed to know.