I guess you want the next year as a default year when you open your date picker, right? I know you mentioned adding 1, but I guess you did it wrong. Just do the following:
Calenar c = Calendar.getInstance();
new DatePickerDialog(Inserisci_entrate_uscite.this, d2,
c.get(Calendar.YEAR) + 1,
dateAndTime.get(Calendar.MONTH),
dateAndTime.get(Calendar.DAY_OF_MONTH))
.show();
This should return the next year even if many dialogs are opened. (If the dateAndTime is the current date).