Alert weergeven bij het laden

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Berichtvenster extends JFrame {

     public static void main(String[] args) {
          JOptionPane.showMessageDialog(null, "Eerste Alert.");
          JOptionPane.showMessageDialog(null, "Tweede Alert.");
          System.exit(0);
     }
}

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class Berichtvenster extends JFrame {
 
     public static void main(String[] args) {
          JOptionPane.showMessageDialog(null, "Eerste Alert.");
          JOptionPane.showMessageDialog(null, "Tweede Alert.");
          System.exit(0);
     }
}