Numeros Enteros A Romanos [Java]

Aplicacion en Modo Consola de Java. Donde Ingresaremos Un Numero Entero Y Nos Retornara, El Numero Entero En Romano
Ejemplo:

Numero Ingresado 20 = XX

Codigo Fuente:

import javax.swing.JOptionPane;
public class Romanos {

    /**
     * @param args
     */
    public static void main (String[] args) {
        //ingreso de total de arreglos
        int num = Integer.parseInt(JOptionPane.showInputDialog("Ingrese Total De Numeros",1));
        //declaramos el Arreglo
        int numeros[] = new int[num];
        //ingresar numeros
        for (int i=0;i<numeros.length;i++){
            numeros[i]= Integer.parseInt(JOptionPane.showInputDialog("Ingreso Nº " + (i+1) + " : ",1 ));
        }
        //mostrar y convertir
        String Str ="";
        for (int i=0;i<numeros.length;i++){
            Str = Str + "Numero " + numeros[i] + " = " + Romanos(numeros[i])+"\n";
        }
        JOptionPane.showMessageDialog(null, Str);

       
    }
    //Metodo Para Convertir Numeros Enteros A romanos. Devuelve Una Cadena.
    public static String Romanos(int num){
         int x;
         int mil,cent,dece,unid;
        mil=(num/1000);
        x=num%1000;
        cent=x/100;
        x=num%100;
        dece=x/10;
        unid=num%10;
        String ERDN="";
        switch(mil){
            case 1:
                ERDN = ERDN +"M";
                break;
            case 2:
                ERDN = ERDN +"MM";
                break;
            case 3:
                ERDN = ERDN +"MMM";
                break;
                 }
        switch(cent){
            case 1:
                ERDN = ERDN +"C";
                break;
            case 2:
                ERDN = ERDN +"CC";
                break;
            case 3:
                ERDN = ERDN +"CCC";
                break;
            case 4:
                ERDN = ERDN +"CD";
                break;
            case 5:
                ERDN = ERDN +"D";
                break;
            case 6:
                ERDN = ERDN +"DC";
                break;
            case 7:
                ERDN = ERDN +"DCC";
                break;
            case 8:
                ERDN = ERDN +"DCCC";
                break;
            case 9:
                ERDN = ERDN +"CM";
                break;
        }
        switch(dece){
            case 1:
                ERDN = ERDN +"X";
                break;
            case 2:
                ERDN = ERDN +"XX";
                break;
            case 3:
                ERDN = ERDN +"XXX";
                break;
            case 4:
                ERDN = ERDN +"XL";
                break;
            case 5:
                ERDN = ERDN +"L";
                break;
            case 6:
                ERDN = ERDN +"LX";
                break;
            case 7:
                ERDN = ERDN +"LXX";
                break;
            case 8:
                ERDN = ERDN +"LXXX";
            case 9:
                ERDN = ERDN +"XC";
                break;
                }
        switch(unid){
            case 1:
                ERDN = ERDN +"I";
                break;
            case 2:
                ERDN = ERDN +"II";
                break;
            case 3:
                ERDN = ERDN +"III";
                break;
            case 4:
                ERDN = ERDN +"IV";
                break;
            case 5:
                ERDN = ERDN +"V";
                break;
            case 6:
                ERDN = ERDN +"VI";
                break;
            case 7:
                ERDN = ERDN +"VII";
                break;
            case 8:
                ERDN = ERDN +"VIII";
                break;
            case 9:
                ERDN = ERDN +"IX";
                break;

        }
        return ERDN;
    }
}