Question

I wrote this following java code to format the date and time in specific formats. You can see the below code at ideone .

import java.util.Calendar;
import java.util.GregorianCalendar;
import java.text.SimpleDateFormat;
class timeAndDateTransformation{
    public static void main(String[] argv){
            Calendar newDate = new GregorianCalendar(2009,7,1,15,20,00);
            SimpleDateFormat dateFormant = new SimpleDateFormat("yyyy/MM/dd");
            SimpleDateFormat timeFormant = new SimpleDateFormat("HH:mm:ss");
            System.out.println(dateFormant.format(newDate.getTime()).toString());
            System.out.println(timeFormant.format(newDate.getTime()).toString());
    }

}

Its giving me following output:

2009/08/01
15:20:00

In this output rest all it perfectly okay, except the month. I passed 7 as a month but in this for-matter output its giving 8 as a output. Please point me where am i doing wrong. I am not very familiar with the date/calendar classes of java, so please bear with me.

Answer 1

Months are 0-based, you passed in 7 so that resolves to August.

From the api docs for java.util.Date:

A month is represented by an integer from 0 to 11; 0 is January, 1 is February, and so forth; thus 11 is December.

It’s really counter-intuitive to make the month zero-based. I think we’ve all gotten burned by that one at some point.