How to obtain Calender ID through Google Calendar API

I have doubt regarding Google calendar API.I had created calendar using google cale开发者_如何学JAVAndar developer guide. I want to retrieve the calendar Id through program. How is it possible?

The final line in the developer guide is:

CalendarEntry returnedCalendar = myService.insert(postUrl, calendar);

Look at the ID of returnedCalendar:

String id = returnedCalender.getId();