java Joda Time difference between two dates

        /**
	 * Renvoie le nombre année, mois et jours entre deux dates sous forme de string formaté !
	 * 
	 */
	public static String toDifferenceBetween2Dates( Date start, Date end )
	{
		Period period = new Period( new DateTime( start ), new DateTime( end ), PeriodType.yearMonthDay() );
		String years = period.getYears() > 0 ? period.getYears() + "a " : "";
		String months = period.getMonths() > 0 ? period.getMonths() + "m " : "";
		String days = period.getDays() > 0 ? period.getDays() + "j" : "";
		return years + months + days;
	}