Re: Calendar question

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 25 Mar 2010 11:19:45 -0700 (PDT)
Message-ID:
<02c1ece6-ff4b-4a80-a7be-d9dcef5f5f12@f8g2000yqn.googlegroups.com>
On Mar 25, 2:12 pm, Rhino <no.offline.contact.ple...@example.com>
wrote:

Jean-Baptiste Nizet <jni...@gmail.com> wrote innews:27538630-6525-438e-ad=

4b-2ad35a5fecc5@v20g2000yqv.googlegroups.com:

On 25 mar, 14:44, Rhino <no.offline.contact.ple...@example.com> wrote:

Can someone clarify for me the difference between:

GregorianCalendar now = new GregorianCalendar();


This one creates a new instance of GregorianCalendar.

and

Calendar now = Calendar.getInstance();


This one creates a Calendar instance. The concrete type of the created
Calendar instance depends on the default timezone and locale. If you
look at the source code, you'll discover that it usually creates a
GregorianCalendar instance, but can also create a BuddhistCalendar or
JapaneseImperialCalendar instance.

and

Calendar now = GregorianCalendar.getInstance();


This one actually calls Calendar.getInstance(), since there is no
getInstance method in GregorianCalendar. It's thus exactly the same as
the previous one, except I would consider it bad style.


My mistake; I misremembered a line I had seen in the Calendar API which
said Calendar rightnow = Calendar.getInstance().

I'm really not clear on what each does and when I would prefer one
over t

he

other.


If you want a Calendar instance that is the most appropriate for the
country and locale of the system where your app is executing, use
Calendar.getInstance(). If you *need* a GregorianCalendar, regardless
of the default locale and timezone, use new GregorianCalendar().

JB.

(I assume each one is preferred in some situation or another.)

--
Rhino


Thank you, that is helpful!


And eerily reminiscent of:

Use 'new GregorianCalendar()' when you specifically want to construct
a 'GregorianCalendar' and not some other 'Calendar' type. You might
want this if the default 'Calendar' for the platform is some other
type, or if you want to control aspects not provided by the 'Calendar'
type, e.g., leap years.
For all other purposes, especially if you particularly want the
'Calendar' native to the host platform, use 'Calendar.getInstance()'.
In practice, this is nearly all the time.


--
Lew

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