belajar joptionpane java

import javax.swing.JOptionPane;
public class joption2 {
       
    public joption2() {
    }
    public static void main(String[] args) {
     String name="";
     name= JOptionPane.showInputDialog("please enter your name");
     String msg="hello"+name+"!";
     JOptionPane.showMessageDialog(null,msg);
    }
}