import javax.swing.JFrame;
import javax.swing.JPanel;


public class Window extends JFrame {

    /**
     *
     */
    private static final long serialVersionUID = -8255319694373975038L;

    public static void main(String[] args){

        new Window();
    }


    public Window(){


        // Adds the custom panel
        Panel Panel = new Panel();
        this.add(Panel);


        // Basic Window Features
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(800,800);
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }


}

public class Panel extends JPanel{

    public Panel(){
        Button testButton = new Button("Test");
        DrawBoard drawBoard = new DrawBoard();
        Listener listener = new Listener();



        this.add(testButton);
        this.add(drawBoard);


    }
}

import java.awt.Dimension;

import javax.swing.JButton;

public class Button extends JButton{


    public Button(String name) {
        this.setText(name);
        this.setName((String) name);
        buttonSettings();
    }

    private void buttonSettings(){
        Listener listener = new Listener();
        this.addActionListener(listener);

        int width = 200;
        int height = 50;
        Dimension dim = new Dimension(width,height);
        this.setPreferredSize(dim);
    }

}

import java.awt.Color;
import java.awt.Dimension;

import javax.swing.JPanel;

public class DrawBoard extends JPanel{

    public DrawBoard(){
        DrawBoardSettings();
    }

    private void DrawBoardSettings(){
        int width = 600;
        int height = 600;
        Dimension dim = new Dimension(width,height);
        this.setPreferredSize(dim);
        this.setBackground(Color.WHITE);
    }
}

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JComponent;

public class Listener implements ActionListener, MouseListener {

    @Override
    public void mouseClicked(MouseEvent e) {
        **// Draw a dot at the mouse location of the DrawBoard JPanel that was added by the Panel JPanel that was added by the Window JFrame**

    }

    @Override
    public void mousePressed(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseReleased(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String name = ((JComponent) e.getSource()).getName();
        **// Draw a rectangle on the DrawBoard JPanel that was added by the Panel JPanel that was added by the Window JFrame**
    }

}