java - Get first next Monday after certain date?

Question

I know there is the same question here, but I have tried the answer provided and it returned an output that I don't understand. I am confused by the answer and I don't think the output is correct.

I need help, thank you :)

GregorianCalendar date1 = new GregorianCalendar( 2014, 05, 12 ); //05 is june as month start from 0 -11

while( date1.get( Calendar.DAY_OF_WEEK ) != Calendar.MONDAY )
    date1.add( Calendar.DATE, 1 );  

System.out.println(date1);

Here is the output:

java.util.GregorianCalendar[time=1405267200000,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Singapore",offset=28800000,dstSavings=0,useDaylight=false,transitions=9,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2014,MONTH=6,WEEK_OF_YEAR=29,WEEK_OF_MONTH=3,DAY_OF_MONTH=14,DAY_OF_YEAR=195,DAY_OF_WEEK=2,DAY_OF_WEEK_IN_MONTH=2,AM_PM=0,HOUR=0,HOUR_OF_DAY=0,MINUTE=0,SECOND=0,MILLISECOND=0,ZONE_OFFSET=28800000,DST_OFFSET=0]

Where on the output should I extract to retrieve Monday's date?

Answer 1

Java 8+

LocalDate ld = LocalDate.of(2014, Month.JUNE, 12);
System.out.println(ld);
ld = ld.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println(ld);

Which prints...

2014-06-12
2014-06-16

Because it's possible that the date my actually be a Monday, you could also use...

ld = ld.with(TemporalAdjusters.nextOrSame(DayOfWeek.MONDAY));

Java <= 7

You should be using the ThreeTen Backport, which gives you the support of the Java 8 Date/Time API

Original Answer

Instead of System.out.println(date1); use System.out.println(date1.getTime());

getTime returns an instance of Date which represents the current state of the Calendar

Which will output Mon Jul 14 00:00:00 EST 2014

System.out.println(date1) is the equivlent of using System.out.println(date1.toString()), which, in this case, is dumping a bunch of useful info about the state of the Calendar object, but not really human readable data.

System.out.println(date1.getTime()) will use the Date's to toString method to display a date value, formatted based on the current local settings, which will provide more useful information.

Updated

Instead of using GregorianCalendar, you should use the system Calendar, for example...

Calendar date1 = Calendar.getInstance();
date1.set(2014, 06, 12);

Also, months are 0 indexed, meaning that Janurary is actually 0 not 1, so in your example, you've specified the month as July, not June.

So, instead, using...

Calendar date1 = Calendar.getInstance();
date1.set(2014, 05, 12);

while (date1.get(Calendar.DAY_OF_WEEK) != Calendar.MONDAY) {
    date1.add(Calendar.DATE, 1);
}

System.out.println(date1.getTime());

Which outputted...

Mon Jun 16 16:22:26 EST 2014

Which is next Monday from today...more or less ;)