DouKaku?

import java.util.*;
import static java.util.Calendar.*;
public class Count13Friday {

    public static void main(String[] args) {
        Calendar to = new GregorianCalendar(2013, 12, 31);
        Calendar current = new GregorianCalendar();

        int currentDate = current.get(DATE);
        if (currentDate != 13) {
            current.set(DATE, 13);
            if (13 < currentDate) {
                current.add(MONTH, 1);
            }
        }

        List<Date> fridays = new ArrayList<Date>();
        while (current.compareTo(to) <= 0) {
            if (current.get(DAY_OF_WEEK) == FRIDAY) {
                fridays.add(current.getTime());
            }
            current.add(MONTH, 1);
        }
        System.out.println("Fridays = " + fridays);
    }

}