Calendar behaves diffrently than Date

Question

Dear all,
I have used IBM jax-ws for webservice ... in which I have an instance of Calendar ... and I used a Hibernate Query which used Date ...
Then I realized that I got a wrong result (A hidden bug in an application since last year).
Please see the code below:
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class CalendarTest {
      * @param args
      * @throws ParseException
     public static void main(String[] args) throws ParseException {
          DateFormat formatter = new SimpleDateFormat("yy-mm-dd");
          Date date1 = (Date) formatter.parse("2010-01-20");
          System.out.println("date1 = " + date1.toString());
          Calendar cal = new GregorianCalendar(2010, 1, 20);
          Date date2 = cal.getTime();
          System.out.println("date2 = " + date2.toString());
}The results are
date1 = Wed Jan 20 00:01:00 CET 2010
date2 = Sat Feb 20 00:00:00 CET 2010
Why is there this difference?
Best regards,
Pengyou

Answer 1

dcminter wrote:
Because (1) Date and Calendar are different classes and (2) "mm" is the symbol for "minute" not "month".But the result is right for Date as "date1 = Wed Jan 20 00:01:00 CET 2010", it is indeed the entered value
"Date date1 = (Date) formatter.parse("2010-01-20");"
Anyhow my problem is about Calendar with gives the wrong result as
"date2 = Sat Feb 20 00:00:00 CET 2010" is not what I entered by "Calendar cal = new GregorianCalendar(2010, 1, 20);"
PS: I changed "yy-mm-dd" to "yy-MM-dd".
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class CalendarTest {
      * @param args
      * @throws ParseException
     public static void main(String[] args) throws ParseException {
          DateFormat formatter = new SimpleDateFormat("yy-MM-dd");
          Date date1 = (Date) formatter.parse("2010-01-20");
          System.out.println("date1 = " + date1.toString());
          Calendar cal = new GregorianCalendar(2010, 1, 20);
          Date date2 = cal.getTime();
          System.out.println("date2 = " + date2.toString());
}