import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class MojeOkno extends JFrame {
    private JButton button;
    private JLabel jLabel;
    private Point point;
    MojeOkno()
    {
        super("Okno");
        this.setLayout(new FlowLayout());
        button = new JButton();
        button.setSize(100,100);
        button.setText("Elo witam");
        point = new Point();

        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("elo tutaj po kliknieciu buttona");
            }
        });

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(800,800);
        this.add(button);
        this.add(point);
        setVisible(true);
    }
}


import java.awt.*;

public class Main {

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MojeOkno();
            }
        });


    }
}
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Random;
import javax.swing.JPanel;

public class Point extends JPanel {

    public Point() {
        setPreferredSize(new Dimension(200, 200));
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2d = (Graphics2D) g;

        g2d.setColor(Color.red);
        g2d.fillRect(100,100,10,10);
    }

}