Custom Format Number

DecimalFormatSymbols sym = new DecimalFormatSymbols();
sym.setGroupingSeparator('-');
NumberFormat accFormatter = new DecimalFormat("###,###,####,######",sym);
BigDecimal num = new BigDecimal("1111111111111111");
String formattedNum = accFormatter.format(num);


formattedNum = 111-111-1111-111111