GUIs

import javax.swing.*;

public class UsingSwingForInput {
    public static void main(String[] args) {
        String name = JOptionPane.showInputDialog("What is your name?");
        String input = JOptionPane.showInputDialog("How old are you?");
        int age = Integer.parseInt(input);

        System.out.print("Hello, " + name + ". ");
        System.out.println("Next year, you'll be " + (age + 1));

        System.exit(0);
    }
}

import javax.swing.*;

public class BoringWindow {
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(300, 200);
        f.setVisible(true);
    }
}

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

public class FrameWithAPanelWithWritingOnIt {
    public static void main(String[] args) {
        Frame613 f = new Frame613();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    }
}

class Frame613 extends JFrame {
    public Frame613() {
        setTitle("613 rocks!");
        setSize(300, 200);
        setLocation(100, 200);

        Panel613 panel = new Panel613();
        Container cp = getContentPane();
        cp.add(panel);
    }
}

class Panel613 extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawString("Hi", 75, 100);
    }
}