Calendar giving wrong day of week

Question

I have a calendar object as below that represents 08 Aug 2014.It is a Friday. So myCal.get(Calendar.DAY_OF_WEEK) should be 6. But it gives 2. Why is that?

java.util.GregorianCalendar[time=1410177767000,areFieldsSet=true,lenient=true,zone=Asia/Calcutta,firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2014,MONTH=8,WEEK_OF_YEAR=37,WEEK_OF_MONTH=2,DAY_OF_MONTH=8,DAY_OF_YEAR=251,DAY_OF_WEEK=2,DAY_OF_WEEK_IN_MONTH=2,AM_PM=1,HOUR=5,HOUR_OF_DAY=17,MINUTE=32,SECOND=47,MILLISECOND=0,ZONE_OFFSET=19800000,DST_OFFSET=0]

Answer 1

I have a calendar object as below that represents 08 Aug 2014.

It doesn't: MONTH=8 is September, not August (month numbering starts from zero).

You can verify yourself by noting DAY_OF_YEAR=251 in your output. The 251st day of a non-leap year is 8 September.

Another way to check the timestamp is by pasting 1410177767000 into http://www.epochconverter.com/

Answer 2

The GregorianCalender takes month for august as '7' and not '8' since January is represented as '0'. Reference : Gregorian Calendar

So kindly check the following and it should work.

   import java.util.*;

   public class Test {
       public static void main(String args[]) {
           GregorianCalendar myCal = new GregorianCalendar(2014, 7, 8);
           System.out.println(myCal.get(Calendar.DAY_OF_WEEK));
       }
   }

Answer 3

tl;dr

Use java.time classes rather than terrible legacy date-time classes with their crazy month numbering.

LocalDate                     // Represent a date-only value, without time-of-day, without offset, without time zone.
.of( 2014 , 8 , 8 )           // Or use `Month.AUGUST`.
.getDayOfWeek()               // Returns `DayOfWeek` enum object.
.equals( DayOfWeek.FRIDAY )   // Returns true/false.

true

java.time

You are using terrible app old date-time classes that were supplanted years ago by the java.time classes.

Sane numbering

Represent a date-only value with LocalDate. Note the sane numbering, unlike the legacy classes: 2014 means the year 2014, and months 1-12 mean January-December. So your problem of inadvertently using the wrong month is moot, and never would have occurred if you’d been using the modern and well-designed java.time classes.

LocalDate ld = LocalDate.of( 2014 , 8 , 8 ) ;

For more clarity, use the Month enum. So month 8 is Month.AUGUST.

LocalDate ld = LocalDate.of( 2014 , Month.AUGUST , 8 ) ;

Ask for the DayOfWeek enum object representing the day-of-week on that date.

DayOfWeek dow = ld.getDayOfWeek() ;

Convert

If you have a GregorianCalendar object in hand given by old code not yet updated to java.time, convert. Convert to a ZonedDateTime. Then extract the DayOfWeek.

ZonedDateTime zdt = myGregCal.toZonedDateTime() ;
DayOfWeek dow = zdt.getDayOfWeek() ;

Answer 4

As our friends said, the count starts from 0. So, January is month 0.

If you came here probably you have the code already done. In order to avoid reviews in code you could do:

currentDateMonth = calendar.get(Calendar.MONTH);

currentDateMonth = currentDateMonth+1;