code: public String getMessage() {
          if (messageParameters != null) {
              try {
                  return MessageFormat.format(super.getMessage(), (Object[]) getMessageParameters());
              } catch (Throwable t) {
                  return super.getMessage();
              }
          } else {
              return super.getMessage();
          }
      }
docs: Returns the error message string of this throwable object.
  <p>
  
  Overrides the method in {@link Throwable} to allow for parameter
  insertion. If parameter insertion fails though, the message is returned
  without parameters inserted into the message String.
  
  @return the error message string of this exception