regex strangeness

ParseRun.java

    public static Calendar startCalendarFromFilename(String bookPath) {
//        format is YYYYMMDD
        String datePattern = "\\D+(\\d{4})(\\d{2})(\\d{2})\\.csv\\.gz";
        Pattern dateRe = Pattern.compile(datePattern);
        Matcher matcher = dateRe.matcher(bookPath);
        Calendar startDate;
        if (matcher.groupCount() == 3) {
            System.out.println("Got match on:" + matcher.toString());
            System.out.println("Group 0:" + matcher.group(0));

            startDate = Calendar.getInstance();
            startDate.set(Integer.valueOf(matcher.group(1)),
                          Integer.valueOf(matcher.group(2)),
                          Integer.valueOf(matcher.group(3)));

            return startDate;
        }

        return null;
    }