Creating a JFace ApplicationWindow with MenuBar

Main.java:

import org.eclipse.jface.dialogs.*;
import org.eclipse.jface.action.*;
import org.eclipse.jface.window.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.*;
 
public class Main extends ApplicationWindow {
   public Main(Shell parent) {
      super(parent);
   }
   
   public static void main(String []args) {
      Display display = new Display();
      Shell shell = new Shell(display);
      
      Main main = new Main(shell);
      main.createComponents();
      main.open();
   }
 
   public void createComponents() {
      setBlockOnOpen(true);
      addMenuBar();
   }
   
   protected MenuManager createMenuManager() {
      MenuManager menuManager = new MenuManager();
      menuManager.add(createFileMenu());
      return menuManager;
   }
   
   protected MenuManager createFileMenu() {
      MenuManager menu = new MenuManager("&File", "Id01");

      menu.add(new Action() {
         public String getText() {
            return "&Open";
         }
         
         public void run() {
            String[] buttons = { IDialogConstants.OK_LABEL,
                                  IDialogConstants.CANCEL_LABEL };
            MessageDialog dialog = new MessageDialog(getShell(), "Title", null, 
                                                     "File/Open selected!", 
                                                     MessageDialog.INFORMATION, buttons, 0);
            dialog.open();   // blocking call
         }
      });

      menu.add(new Action() {
         public String getText() {
            return "E&xit";
         }
         
         public void run() {
            Main.this.getParentShell().close();
         }
      });
       
      return menu;
   }
    
   protected void configureShell(Shell shell) {
      super.configureShell(shell);
      shell.setSize(300, 200);
      shell.setText("Example JFace with MenuBar");
   }  
}