Überschrift

public class HexinDez {

/**
* @author Montin, Rene
*/

public static void main(String[] args) {

             //nötiges Kommando zum Einlesen in die Kommandozeile
             BufferedReader eingabe = new BufferedReader(new InputStreamReader 
             (System.in));
            
             //Variablendeklaration
             int zahl;
             int rest;
             int modulo;
             String hexa = "";
             String ausgabe = "";
             
             //Konsolenausgabe
             System.out.println("Geben Sie eine beliebige Zahl ein (im Hexadezimalsystem): ");
         try{
             //Einlesen von Kommandozeile
             zahl = Integer.parseInt(eingabe.readLine());
             rest = zahl;
             while(rest > 0){ //solange folgende Bedingung zutrifft
                      modulo = rest % 16;
                      rest = rest / 16;
                          switch (modulo){  //Abchecken der Bedingung
                                case 0: hexa = "0";
                                break;
                                case 1: hexa = "1";
                                break;
                                case 2: hexa ="2";
                                break;
                                case 3: hexa ="3";
                                break;
                                case 4: hexa ="4";
                                break;
                                case 5: hexa = "5";
                                break;
                                case 6: hexa = "6";
                                break;
                                case 7: hexa = "7";
                                break;
                                case 8: hexa ="8";
                                break;
                                case 9: hexa ="9";
                                break;
                                case 10: hexa ="A";
                                break;
                                case 11: hexa ="B";
                                break; 
                                case 12: hexa ="C"; 
                                break;
                                case 13: hexa = hexa + "D";
                                break;
                                case 14: hexa = hexa + "E";
                                break;
                                case 15: hexa = hexa + "F"; 
                                break; 
                        }
                        ausgabe = hexa + ausgabe;
             }

             if (ausgabe == ""){  //sollte die Variable ausgabe keinen Wert enthalten
                 ausgabe = "0";
                 System.out.println(ausgabe + "im Hexadezimalsystem");
             }
             System.out.println(ausgabe + " im Hexadezimalsystem");
      }catch (IOException io){ //Ausnahmebedingung
             System.out.println("Problem beim Einlesen von Konsole");
      }
    }
}