Bin to Hex is KILLING ME, any advice?

Question

   public static String fromBinToHex(String binNum)
         String hexNum = "";
         String a = "1011111011101111";
         int n = a.length();
                for (int f = 0 ; f < a.length(); f++)
               switch (n.charAt(f+4))
                case '1010' : hexNum += "A"; break;
         return hexNum;
    }    Thats basically what I got. I'm trying to get this
System.out.println("11100100100110110 Base-2 converts to " + BaseConverter.fromBinToHex("11100100100110110") + " in Base-16.\n");The Bin is basically supposed to spit out "BEEF" in hex form.
Much help is appreciated :)

Answer 1

^ Response
Is it something like this? I did this for the Hex to Bin Converter.
    public static String fromHexToBin(String hexNum)
         String binNum = "";
          for (int k = 0 ; k < hexNum.length(); k++)
               switch (hexNum.charAt(k))
                    case '0' : binNum += "0000"; break;
                    case '1' : binNum += "0001"; break;
                    case '2' : binNum += "0010"; break;
                    case '3' : binNum += "0011"; break;
                    case '4' : binNum += "0100"; break;
                    case '5' : binNum += "0101"; break;
                    case '6' : binNum += "0110"; break;
                    case '7' : binNum += "0111"; break;
                    case '8' : binNum += "1000"; break;
                    case '9' : binNum += "1001"; break;
                    case 'A' : binNum += "1010"; break;
                    case 'B' : binNum += "1011"; break;
                    case 'C' : binNum += "1100"; break;
                    case 'D' : binNum += "1101"; break;
                    case 'E' : binNum += "1110"; break;
                    case 'F' : binNum += "1111"; break;
          return binNum;
     }