import java.awt.Graphics2D;
import java.awt.event.*;
import java.awt.image.BufferStrategy;
import java.util.ArrayList;
//import java.util.Map;
//import java.util.Random;

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


public class J_Verne extends Canvas implements KeyListener, MouseListener , MouseMotionListener {
...

JPanel panel = (JPanel)ventana.getContentPane();
setBounds(0,0,SCREEN_WIDTH,SCREEN_HEIGHT);
        panel.setPreferredSize(new Dimension(SCREEN_WIDTH,SCREEN_HEIGHT));
        panel.setLayout(null);
        panel.setFocusable(true);
        panel.add(this);
        panel.addMouseMotionListener(this);
        
        panel.addKeyListener(this);
        panel.grabFocus();
}


public void mouseMoved(MouseEvent arg0) {
		Point a = arg0.getLocationOnScreen();
		mouse_x = a.x;
		mouse_y = a.y;
		System.out.println(mouse_x+" - carp -  "+mouse_y);
	}