I copied some text from NSDate Reference as below, please check Return Value, 
it is said the format will be in YYYY-MM-DD HH:MM:SS ±HHMM, but I got as below 
in my app, so the reference is mistake? or code in mistake?

Saturday, January 1, 2011 12:00:00 AM Japan Standard Time
or
2011?1?1????0?00?00? ?????

descriptionWithLocale:
Returns a string representation of the receiver using the given locale.

- (NSString *)descriptionWithLocale:(id)locale
Parameters
locale
    An NSLocale object.

    If you pass nil, NSDate formats the date in the same way as the description
method.

    On Mac OS X v10.4 and earlier, this parameter was an NSDictionary object. 
If you pass in an NSDictionary object on Mac OS X v10.5, NSDate uses the 
default user locale—the same as if you passed in [NSLocale currentLocale].

Return Value
    A string representation of the receiver, using the given locale, or if the
locale argument is nil, in the international format YYYY-MM-DD HH:MM:SS ±HHMM,
where ±HHMM represents the time zone offset in hours and minutes from GMT (for
example, “2001-03-24 10:45:32 +0600”)