code: private static String createString(byte bytes[])
      {
          StringBuilder sb = new StringBuilder();
          if (bytes == null)
          {
              sb.append("null");
          }
          else
          {
              for (byte b : bytes)
              {
                  if (Character.isLetterOrDigit(b) || Character.isWhitespace(b))
                  {
                      sb.append((char)b);
                  }
              }
          }
          return sb.toString();
      }
docs: Creates a String from the letter, digit and whitespace
  characters in the given byte array
  
  @param bytes The bytes for the String
  @return The String