...
GregorianCalendar d1 = new GregorianCalendar(TimeZone.getTimeZone("ECT"));
d1 = new GregorianCalendar(y1,2,15,0,0);
SimpleDateFormat formater = new SimpleDateFormat("dd.MM.yyyy");
System.out.println("d1 -> SimpleDateFormat: "+formater.format(d1.getTime()));
/** Datum 2 */
GregorianCalendar d2 = new GregorianCalendar(y2,11,31,0,0);
System.out.println("d2 -> SimpleDateFormat: "+formater.format(d2.getTime())+"\n");
// Hole Millisek. von jedem Datum und subtrahiere.
long diff = d2.getTimeInMillis() -d1.getTimeInMillis();
System.out.println("Anzahl Tage zwischen " + d1.get(Calendar.DATE)+ "." +
(d1.get(Calendar.MONTH)+1) + "." +
d1.get(Calendar.YEAR) +
" und " + d2.get(Calendar.DATE) + "." +
(d2.get(Calendar.MONTH)+1) + "." +
d2.get(Calendar.YEAR) + ": "+
(diff / (1000*60*60*24)+1) +
" Tage.");
...