Swing_Simple_Base_Program_Structures/SingleFile/Main.java

package SingleFile;

import javax.swing.JButton;
import javax.swing.JFrame;

import java.awt.FlowLayout;

public class Main {
    private static int counter; 
    public static void main(String[] args) {
        counter = 0;

        JFrame jFrame = new JFrame("My Single File Counter GUI");

        jFrame.setLayout(new FlowLayout(FlowLayout.CENTER));
        jFrame.setSize(300, 200);

        JButton button = new JButton();
        button.setText("Click Me!");
        button.addActionListener((v) -> {
            counter += 1;

            button.setText("You've clicked the button " + counter + " times!");
        });

        jFrame.add(button);
        jFrame.setVisible(true);
    }
}