Return a Date set to the first possible millisecond of the month, just after midnight in Java
Description
The following code shows how to return a Date set to the first possible millisecond of the month, just after midnight.
Example
/*from w w w.j ava 2s.c om*/
import java.util.Calendar;
import java.util.Date;
public class Main {
public static Date getStartOfMonth(Date day) {
return getStartOfMonth(day, Calendar.getInstance());
}
public static Date getStartOfMonth(Date day, Calendar cal) {
if (day == null)
day = new Date();
cal.setTime(day);
// set time to start of day
cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
cal.set(Calendar.MINUTE, cal.getMinimum(Calendar.MINUTE));
cal.set(Calendar.SECOND, cal.getMinimum(Calendar.SECOND));
cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
// set time to first day of month
cal.set(Calendar.DAY_OF_MONTH, 1);
return cal.getTime();
}
public static void main(String[] argv) {
System.out.println(getStartOfMonth(new Date()));
}
}
The code above generates the following result.