Некорректно отображает время (без нуля впереди)

private int years;
private int month;
private int day;
private int hour;
private int min;

......

    tv = (TextView)findViewById(R.id.tv);

    final Calendar c = Calendar.getInstance();
    years = c.get(Calendar.YEAR);
    month = c.get(Calendar.MONTH);
    day = c.get(Calendar.DAY_OF_MONTH);
    min = c.get(Calendar.MINUTE);

    updateDisplay();
}

private void updateDisplay() {
    // TODO Auto-generated method stub
    tv.setText(
        new StringBuilder()
            .append(month + 1).append("-")
            .append(day).append("-")
            .append(years).append(" ")
            .append(hour).append(":")
            .append(min).append(" ")
    );}

private String pad(int c) {
    if (c >= 10) return String.valueOf(c);
    else return "0" + String.valueOf(c);

}
}