Simple GUI

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

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

public class GUI {

    public static void main(String[] args) {
        GUI gui = new GUI();
    }

    private int count = 0;

    public GUI() {

        JFrame frame = new JFrame();
        frame.setSize(200, 100);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setTitle("Test GUI");

        JLabel label = new JLabel("0");

        JButton button = new JButton("Click me");
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                count++;
                label.setText(count + "");
            }
        });

        frame.add(label, BorderLayout.CENTER);
        frame.add(button, BorderLayout.SOUTH);

        frame.setVisible(true);
    }

}