I just run into an anoying little bug with SimpleDateFormat......

Question

Try run this code:
Filename: Foo.java
import java.util.*;
import java.text.*;
public class Foo {
  public static void main(String args[]) {
    DateFormat df = new SimpleDateFormat("dd.MM.yyyy");
    Date date = null;
    try {
      date = df.parse("31.12.2002");
    } catch (Exception e) {
      e.printStackTrace();
    System.out.println("Date initiated: "+date.toString());
    df = new SimpleDateFormat("yyyy-ww");
    System.out.println("Week expected is 2003-01");
    System.out.println("Rendered week : "+df.format(date));
End of file
Output from code:
H:\>java Foo
Date initiated: Tue Dec 31 00:00:00 CET 2002
Week expected is 2003-01
Rendered week : 2002-01
Anyone know any workaround to get the expected result?
I am sitting on a DW project that has met this anoying little bug, and I have posted this to the bug parade aswell, but I have no time to wait for a new release of the JDK :) Hope you can help
My os:
Windows 2000 SP 2
My JDK version (cannot use 1.4):
java version "1.3.1_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_04-b02)
Java HotSpot(TM) Client VM (build 1.3.1_04-b02, mixed mode)
Any help is appreciated.

Answer 1

As Sun says, calculations using Date are ok for computers. but if you need to do things that people want to do with dates, use Calendar/GregorianCalendar. Here's a couple of examples
import java.util.*;
import java.text.*;
public class Calendar2 {
    public static void main(String[] args) {
        Calendar cal = Calendar.getInstance(); // today as Calendar obj;
        cal.add(cal.MONTH, 6);
        // change to Date object for better format control;
        Date sixMonthsFromNow = cal.getTime();
        // create custom format;
        DateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
        // apply format and print;
        System.out.println(sdf.format(sixMonthsFromNow));
import java.util.*;
public class Calendar1 {
    public static void main(String[] args) {
        Calendar cal = Calendar.getInstance();
        for( int n = 0; n < 7; n++ ) {
                System.out.println(cal.get(cal.DATE) + "/" + (cal.get(cal.MONTH) + 1) + "/" + cal.get(cal.YEAR));
                cal.add(cal.DATE, 1);
}