Composite in the Wild: Java Swing's Container

import java.awt.Component;
import java.awt.Container;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class CoSwing {
    static int count(Component component) {
        int total = 1;
        if (component instanceof Container container) {
            for (Component child : container.getComponents()) {
                total += count(child);
            }
        }
        return total;
    }

    static void print(Component component, String indent) {
        System.out.println(indent + component.getClass().getSimpleName());
        if (component instanceof Container container) {
            for (Component child : container.getComponents()) {
                print(child, indent + "  ");
            }
        }
    }

    public static void main(String[] args) {
        JPanel buttons = new JPanel();
        buttons.add(new JButton("Save"));
        buttons.add(new JButton("Cancel"));

        JPanel form = new JPanel();
        form.add(new JLabel("Name"));
        form.add(buttons);

        print(form, "");
        System.out.println("components: " + count(form));
        System.out.println("JButton is a Container: " + (new JButton() instanceof Container));
    }
}