How i can get session id in server programme?

I write:
System.out.println
(this.getThreadLocalRequest().getSession(true).getId());
But programme always return different values. Where i mistake?
Explain me please what difference bitwean: getSession(true),
getSession(false) and getSession()? Thank you.

--
You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group.
To post to this group, send email to google-web-toolkit@googlegroups.com.
To unsubscribe from this group, send email to google-web-toolkit+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.