docs: public static void main(String[] args) {
          Settings settings = new Settings();
          new JCommander(settings, args);
  
          if (!settings.isGuiSupressed()) {
              OkapiUI okapiUi = new OkapiUI();
              okapiUi.setVisible(true);
          } else {
              int returnValue;
              
              returnValue = commandLine(settings);
              
              if (returnValue != 0) {
                  System.out.println("An error occurred");
              }
          }
      }