Why can i have only one instance of Calendar object

Question

I was just wondering...

why can i have only one instance of Calendar object. Is there a reason for it to be a singleton?

I have tried to read the documentat

Answer 1

It is not singleton.

This:

public static void main(String args[]) {
        Calendar c1, c2;
        c1 = Calendar.getInstance();
        c2 = Calendar.getInstance();
        c1.add(Calendar.MONTH, 1);
        System.out.println(c1);
        System.out.println(c2);
    }

Outputs:

java.util.GregorianCalendar[time=?,areFieldsSet=false,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Jerusalem",offset=7200000,dstSavings=3600000,useDaylight=true,transitions=143,lastRule=java.util.SimpleTimeZone[id=Asia/Jerusalem,offset=7200000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=26,startDayOfWeek=6,startTime=7200000,startTimeMode=0,endMode=1,endMonth=8,endDay=13,endDayOfWeek=0,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2011,MONTH=5,WEEK_OF_YEAR=21,WEEK_OF_MONTH=3,DAY_OF_MONTH=19,DAY_OF_YEAR=139,DAY_OF_WEEK=5,DAY_OF_WEEK_IN_MONTH=3,AM_PM=0,HOUR=10,HOUR_OF_DAY=10,MINUTE=21,SECOND=27,MILLISECOND=839,ZONE_OFFSET=7200000,DST_OFFSET=3600000]
java.util.GregorianCalendar[time=1305789687839,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Jerusalem",offset=7200000,dstSavings=3600000,useDaylight=true,transitions=143,lastRule=java.util.SimpleTimeZone[id=Asia/Jerusalem,offset=7200000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=26,startDayOfWeek=6,startTime=7200000,startTimeMode=0,endMode=1,endMonth=8,endDay=13,endDayOfWeek=0,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2011,MONTH=4,WEEK_OF_YEAR=21,WEEK_OF_MONTH=3,DAY_OF_MONTH=19,DAY_OF_YEAR=139,DAY_OF_WEEK=5,DAY_OF_WEEK_IN_MONTH=3,AM_PM=0,HOUR=10,HOUR_OF_DAY=10,MINUTE=21,SECOND=27,MILLISECOND=839,ZONE_OFFSET=7200000,DST_OFFSET=3600000]

(Which is different as you can see)

BTW, quick search for source code returns:

public static synchronized Calendar getInstance() {
       return new GregorianCalendar();
}