Incorrect WEEK_OF_YEAR for Gregorian Calendar

The date is initially set to 31 Dec 2000. The year is then rolled to 2001. The WEEK_OF_YEAR should then be 53 (at least according to the behaviour of 1.1.7). For 1.1.8, WEEK_OF_YEAR=1.

import java.util.*;
import java.text.*;

public class RollYear {

    RollYear() {
        GregorianCalendar cal = new GregorianCalendar();
        cal.setLenient(true);
        cal.setFirstDayOfWeek(2); // Monday
        cal.setMinimalDaysInFirstWeek(4);
        cal.set(2000, 11, 31);
        System.out.print("Initial date : ");
        displayDate(cal);
        cal.roll(cal.YEAR, true); // roll up year by 1
        System.out.print("Rolled to : ");
        displayDate(cal);
        // WEEK_OF_YEAR should now be 53
        int woy = cal.get(cal.WEEK_OF_YEAR);
        if (woy != 53) {
            throw new RuntimeException("Test Failed: WEEK_OF_YEAR should now be
 53, not " + woy);
        }
        System.out.print("Test Passed");
    }

    void displayDate(GregorianCalendar gc) {
        SimpleDateFormat sdf = new SimpleDateFormat();
        sdf.applyPattern("dd MMM yyyy");
        Date displayDate = gc.getTime();
        System.out.println(sdf.format(displayDate));
    }

    public static void main(String args[]) {
        new RollYear();
    }

}

stuart.lawrence@eng 1998-12-15

There is also a problem when the initial date is 01 Jan 1999 (replace above cal.set(2000, 11, 31) with cal.set(1999, 0, 1)). In this case, after the roll, WEEK_OF_YEAR=0 for 1.1.7 and WEEK_OF_YEAR=53 for 1.1.8 (build C).

stuart.lawrence@eng 1998-12-16