code: public void onError( Exception e ) {
          e.printStackTrace();
          String localizedMessage = e.getLocalizedMessage();
          if (localizedMessage == null) {
              localizedMessage = e.getMessage();
          }
          if (localizedMessage == null || localizedMessage.trim().length() == 0) {
              localizedMessage = "An undefined error was thrown. Please send the below trace to your technical contact:\n";
              localizedMessage += ExceptionUtils.getStackTrace(e);
          }
  
          String _localizedMessage = localizedMessage;
          SwingUtilities.invokeLater(new Runnable(){
              public void run() {
                  JOptionPane.showMessageDialog(parent, _localizedMessage, "ERROR", JOptionPane.ERROR_MESSAGE);
              }
          });
      }
docs: Called if an error occurrs. Can be overridden. SHows dialog by default.
  
  @param e the exception thrown.