GetInstance

Question

is this method a part of an API for a particular class or interface? or is it just a commonly given name for a method in a singleton design pattern?
Can someone explain to me how it works? for instance:
Calendar c = Calendar.getInstance();is that just returning a reference to the calendar object in the Calendar class?
SomeObject o = new SomeObject();o is now an instance of SomeObject, isn't it?

Answer 1

is this method a part of an API for a particular class
or interface? Several, actually.
or is it just a commonly given name for
a method in a singleton design pattern?Yep. Factories too.
Can someone explain to me how it works? for instance:
Calendar c = Calendar.getInstance();is that just returning a reference to the calendar
object in the Calendar class?Well, it depends on which class, obviously, but for Calendar, here's the source. (It comes with the SDK download):
    public static Calendar getInstance()
        return createCalendar(TimeZone.getDefault(), Locale.getDefault());
and createCalendar is
    private static Calendar createCalendar(TimeZone zone,
                            Locale aLocale)
     if (aLocale.getLanguage().compareTo("th") == 0) {
         if (aLocale.getCountry().compareTo("TH") == 0) {
          return new sun.util.BuddhistCalendar(zone, aLocale);
     // else create the default calendar
        return new GregorianCalendar(zone, aLocale);     
SomeObject o = new SomeObject();o is now an instance of SomeObject, isn't it?Yes.