code: @Override
      public String getMessage() {
          String message = super.getMessage();
  
          if (message == null) {
              message = "";
          }
  
          if (hexdump != null) {
              return message + (message.length() > 0 ? " " : "") + "(Hexdump: "
                      + hexdump + ')';
          }
  
          return message;
      }
docs: Returns the message and the hexdump of the unknown part.