How to Create a Java GUI App that shows the Logged-in User and Hostname

import javax.swing.*;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class Application {
    public static void main(String...args) throws UnknownHostException {
        JFrame frame = new JFrame("Sample App");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300,300);

        String user = System.getProperty("user.name");
        String host = InetAddress.getLocalHost().getHostName();

        JTextArea txt = new JTextArea();
        txt.setText(
                "\n" +
                "  User: "+user+"\n" +
                "  Host: "+host+"\n"
        );
        frame.getContentPane().add(txt);

        frame.setVisible(true);
    }
}

java Application.java