"Session will be invalidated after a time-out period defined by Servlet Container" - From HFSJ I know session can be invalidated by invalidate(), or specifying time-out in DD or if the browser crashes. But what is meant by time-out defined by servlet container ? is it a default value specified in servlet container?
If the browser crashes, that does not invalidate your session. You may not be able to get back to the session because you lost the cookie holding the session id, but technically your session is still active until it times out.
Yes, The time interval defined in the DD will be used instead of the Container's default one right. Also You can set the inactive interval by the session method setMaxInactiveInterval(int interval) programmatically.
In DD we define interval in minutes whereas in the above method the time interval is in seconds.