Re: "com.swiftmq.jms.ConnectionLostException: Connection closed"

Transparent Reconnect is enabled by default so the client tries to reconnect until it reaches max-retries. That's apparently what you see. If you want to get informed about connection lost, register a javax.jms.ExceptionListener.

All pending requests wait until the reconnect succeeds or max-retries have been reached. In the latter case the requests are cancelled and the commit returns a JMSException.

You can see the reconnect output if you set

-Dswiftmq.reconnect.debug=true

at your client.