A problem about "multiple"

[jinyunshaobing]

I know how to put a channel in confirm mode.

channel.confirmSelect();

But how can i set multiple = false/true?
And if multiple = false, when channel.ack(2) happened, should i still do channel.ack(1)？

Thank you very much！

[jinyunshaobing]

OK,I found that channel.ack() has two param, the first is deliverTag, the second is flag which can be AMQP::multiple.
So if channel.ack(2), multiple is false by default.
Please let me know if there is something wrong with my understanding.