code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.gui;
  
  import java.io.File;
  
  import javax.swing.SwingUtilities;
  import javax.swing.WindowConstants;
  
  /**
   * Entry point for starting the checkstyle GUI.
   *
   */
  public final class Main {
  
      /** Hidden constructor of the current utility class. */
      private Main() {
          // no code
      }
  
      /**
       * Entry point.
       *
       * @param args the command line arguments.
       */
      public static void main(final String... args) {
          SwingUtilities.invokeLater(() -> {
              createMainFrame(args);
          });
      }
  
      /**
       * Helper method to create the {@code MainFrame} instance.
       *
       * @param args the command line arguments
       */
      private static void createMainFrame(String... args) {
          final MainFrame mainFrame = new MainFrame();
          if (args.length > 0) {
              final File sourceFile = new File(args[0]);
              mainFrame.openFile(sourceFile);
          }
          mainFrame.setTitle("Checkstyle GUI");
          mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
          mainFrame.pack();
          mainFrame.setVisible(true);
      }
  
  }
  