This works
String x = "22/06/2012";
String y = "25/10/2014";
String datestart = x;
String datestop = y;
//DateTimeFormatter format = DateTimeFormat.forPattern("dd/mm/yyyy");
SimpleDateFormat format = new SimpleDateFormat("dd/mm/yyyy");
Date d1 = null;
Date d2 = null;
try {
d1 = format.parse(datestart);
d2 = format.parse(datestop);
DateTime dt1 = new DateTime(d1);
DateTime dt2 = new DateTime(d2);
//Period
period = new Period (dt1,dt2);
//calculate days
int days = Days.daysBetween(dt1, dt2).getDays();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}