ошибочка в программе для перевода чисел в слова

package russianmoney;
 
import java.util.Stack;
public class RussianMoney {
private static enum Ranges {
UNITS, DECADES, HUNDREDS, THOUSANDS, MILLIONS, BILLIONS
};
 
private static Stack<ThreeChar> threeChars;
 
private static class ThreeChar {
 
char h, d, u;
Ranges range;
}
 
public static String digits2text(String s) {
try {
return digits2text(new Double(s));
} catch (NumberFormatException ex) {
System.out.println(ex);
return null;
}
}
 
public static String digits2text(Double d) {
// TODO: Научиться парсить числа > 1000000
String s = d.toString();
int n = s.length() - s.lastIndexOf('.');
if (d == null || d < 0.0 || d > 1000000.0 || n > 3) {
System.out.println("Пока гарантированно преобразуются лишь числа от 0.0 до 1000000.0");
return null;
}
if (n == 2) {
s += "0";
}
String[] sa = s.split("\\.");
threeChars = new Stack<>();
threeChars.push(new ThreeChar());
threeChars.peek().range = Ranges.UNITS;
StringBuilder sb = new StringBuilder(sa[0]).reverse();
for (int i = 0; i < sb.length(); i++) {
if (i > 0 && i % 3 == 0) {
threeChars.push(new ThreeChar());
}
ThreeChar threeChar = threeChars.peek();
switch (i) {
case 0:
threeChar.u = sb.charAt(i);
break;
case 3:
threeChar.range = Ranges.THOUSANDS;
threeChar.u = sb.charAt(i);
break;
case 6:
threeChar.range = Ranges.MILLIONS;
threeChar.u = sb.charAt(i);
break;
case 9:
threeChar.range = Ranges.BILLIONS;
threeChar.u = sb.charAt(i);
break;
case 2:
case 5:
case 8:
threeChar.h = sb.charAt(i);
break;
default:
threeChar.d = sb.charAt(i);
}
}
StringBuilder result = new StringBuilder();
while (!threeChars.isEmpty()) {
ThreeChar thch = threeChars.pop();
if(thch.h == '0' && thch.d == '0' && thch.u == '0' && !threeChars.isEmpty()) continue;
if (thch.h > 0) {
result.append(getHundreds(thch.h));
result.append(' ');
}
if (thch.d > '0') {
if (thch.d > '1' || (thch.d == '1' && thch.u == '0')) {
result.append(getDecades(thch.d));
} else if (thch.d > '0') {
result.append(getTeens(thch.d));
}
result.append(' ');
}
if (thch.u > '0' && thch.d != '1') {
result.append(getUnits(thch.u, thch.range == Ranges.THOUSANDS));
result.append(' ');
}
switch (thch.range) {
case BILLIONS:
if (thch.d == '1' || thch.u == '0') {
result.append("миллиардов");
} else if (thch.u > '4') {
result.append("миллиардов");
} else if (thch.u > '1') {
result.append("миллиарда");
} else {
result.append("миллиард");
}
break;
case MILLIONS:
if (thch.d == '1' || thch.u == '0') {
result.append("миллионов");
} else if (thch.u > '4') {
result.append("миллионов");
} else if (thch.u > '1') {
result.append("миллиона");
} else {
result.append("миллион");
}
break;
case THOUSANDS:
if (thch.d == '1' || thch.u == '0') {
result.append("тысяч");
} else if (thch.u > '4') {
result.append("тысяч");
} else if (thch.u > '1') {
result.append("тысячи");
} else {
result.append("тысяча");
}
break;
default:
if (thch.d == '1' || thch.u == '0' || thch.u > '4') {
result.append("рублей");
} else if (thch.u > '1') {
result.append("рубля");
} else {
result.append("рубль");
}
}
result.append(' ');
}
result.append(sa[1]).append(' ');
switch (sa[1].charAt(1)) {
case '1':
result.append(sa[1].charAt(0) != '1' ? "копейка" : "копеек");
break;
case '2':
case '3':
case '4':
result.append(sa[1].charAt(0) != '1' ? "копейки" : "копеек");
break;
default:
result.append("копеек");
}
char first = Character.toUpperCase(result.charAt(0));
result.setCharAt(0, first);
return result.toString().replaceAll("null", "");
}
 
private static String getHundreds(char dig) {
switch (dig) {
case '1':
return "сто";
case '2':
return "двести";
case '3':
return "триста";
case '4':
return "четыреста";
case '5':
return "пятьсот";
case '6':
return "шестсот";
case '7':
return "семсот";
case '8':
return "восемсот";
case '9':
return "девятьсот";
default:
return null;
}
}
 
private static String getDecades(char dig) {
switch (dig) {
case '1':
return "десять";
case '2':
return "двадцать";
case '3':
return "тридцать";
case '4':
return "сорок";
case '5':
return "пятьдесят";
case '6':
return "шестьдесят";
case '7':
return "семьдесят";
case '8':
return "восемьдесят";
case '9':
return "девяносто";
default:
return null;
}
}
 
private static String getUnits(char dig, boolean female) {
switch (dig) {
case '1':
return female ? "одна" : "один";
case '2':
return female ? "две" : "два";
case '3':
return "три";
case '4':
return "четыре";
case '5':
return "пять";
case '6':
return "шесть";
case '7':
return "семь";
case '8':
return "восемь";
case '9':
return "девять";
default:
return null;
}
}
 
private static String getTeens(char dig) {
String s = "";
switch (dig) {
case '1':
s = "один";
break;
case '2':
s = "две";
break;
case '3':
s = "три";
break;
case '4':
s = "четыр";
break;
case '5':
s = "пят";
break;
case '6':
s = "шест";
break;
case '7':
s = "сем";
break;
case '8':
s = "восем";
break;
case '9':
s = "девят";
break;
}
return s + "надцать";
}
 
public static void main(String[] args) {
System.out.println(RussianMoney.digits2text(new Double(args[0])));
}
}