// MainFrame.java
import java.awt.Container;
import javax.swing.*;
 
 
public class MainFrame extends JFrame
{
    MainPanel mp;
 
 
    public MainFrame ()
    {
        this.setSize (800, 800);
        mp = new MainPanel ();
        Container container = this.getContentPane ();
        container.add (mp);
        this.setVisible (true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
 
 
    public static void main (String args[])
    {
        MainFrame mf = new MainFrame ();
    }
}

// MainPanel.java
import java.awt.*;
import java.util.logging.*;
import javax.swing.*;
 
 
public class MainPanel extends JPanel
{
    Panel1 panel1;
    Panel2 panel2;
 
    public MainPanel ()
    {
        panel1 = new Panel1 (this);
        panel2 = new Panel2 (this);
 
        this.setLayout (new GridLayout (2, 1));
        this.add (panel1);
        this.add (panel2);
    }
 
 
    public void RandomAnimation ()
    {
        for (int i = 0; i < 25; i++)
        {
            try 
            {
                Thread.sleep(50);
                panel1.repaint();
            } 
            catch (InterruptedException ex)
            {
                Logger.getLogger(MainPanel.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }
}

// Panel1.java
import java.awt.*;
import java.util.*;
import javax.swing.*;
 
 
public class Panel1 extends JPanel
{
    Random random;
    MainPanel mp;
 
 
    public Panel1 (MainPanel mainpan)
    {
        random = new Random ();
        mp = mainpan;
    }
 
 
    @Override
    public void paintComponent (Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint (RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
 
        int x = random.nextInt (200) + 100;
        int y = random.nextInt (200) + 100;
 
        System.out.println ("Inside Panel1 paintComponent function.");
 
        g2.setColor (Color.RED);
        g2.fillOval (x, y, 50, 50);        
    }
}

// Panel2.java
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
 
 
public class Panel2 extends JPanel implements ActionListener
{
    JButton animateButton;
    MainPanel mp;
 
 
    public Panel2 (MainPanel mainpan)
    {
        mp = mainpan;
        animateButton = new JButton ("Animate");
        animateButton.addActionListener (this);
        this.add (animateButton);
    }
 
 
    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource () == animateButton)
        {
            mp.RandomAnimation ();
        }
    }
}