Someone

package test;

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class MouseApplet extends Applet {
    private Rectangle box;
    private static final int BOX_Y = 100;
    private static final int BOX_X = 100;
    private static final int BOX_WIDTH = 20;
    private static final int BOX_HEIGHT = 30;
    
    public MouseApplet() {
        box = new Rectangle(BOX_X, BOX_Y, BOX_WIDTH, BOX_HEIGHT);
        
            class MousePressListener extends MouseListener {
            public void mousePressed(MouseEvent event) {
                int x = event.getX();
                int y = event.getY();
                box.setLocation(x, y);
                repaint();
            }
            
            public void mouseReleased(MouseEvent event){}
            public void mouseClicked(MouseEvent event){}
            public void mouseEntered(MouseEvent event){}
            public void MouseExited(MouseEvent event){}
        }
        
        MouseListener listener = new MousePressListener();
        addMouseListener(listener);
    }
    
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D)g;
        g2.draw(box);
    }
}