applet to create cursor "wormholes" connecting different displays

Wormhole.java

// Wormhole.java
// Lingdong Huang 2021, Public domain
// Simple app to create "wormholes" connecting different displays:
// When cursor enters a black patch, it comes out from the other
// Idea inspired by this mac app "Wormhole by Tod LLC": https://macdownload.informer.com/wormhole1/
// I implemented the idea in java to work on Windows
//
// Usage:
// javac Wormhole.java; java Wormhole <x0> <y0> <x1> <y1>
// (arguments being the positions of the two holes)
// Right-click on a hole to exit app.
// Drag hole (slowly) to move it across screen

import javax.swing.JFrame;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseEvent;
import java.awt.Robot;
import java.awt.AWTException;
import java.awt.Color;

public class Wormhole {
    Robot robot;

    public class Hole extends JFrame implements MouseMotionListener, MouseListener{
        Hole other;
        boolean active = true;
        Hole (int x, int y){
            setType(Type.UTILITY);
            setUndecorated(true);
            setVisible(true);
            setSize(50,50);
            setLocation(x,y);
            setAlwaysOnTop(true);
            addMouseListener(this);
            addMouseMotionListener(this);
            getContentPane().setBackground(Color.black);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            
        }
        void setOther(Hole o){
            other = o;
        }
        public void mouseMoved(MouseEvent e){
            // System.out.println(e.getXOnScreen()+","+e.getYOnScreen());
        }
        public void mouseDragged(MouseEvent e){
            setLocation(e.getXOnScreen()-getWidth()/2,e.getYOnScreen()-getHeight()/2);
        }
        public void mouseClicked(MouseEvent e){
            if (e.getButton() == MouseEvent.BUTTON3){
                System.exit(0);
            }
        }
        public void mouseEntered(MouseEvent e){
            if (!active) return;
            int x = other.getX() + other.getWidth()/2;
            int y = other.getY() + other.getHeight()/2;
            robot.mouseMove(x,y);
            other.active = false;
        }
        public void mouseExited(MouseEvent e){
            active = true;
        }
        public void mousePressed(MouseEvent e){

        }
        public void mouseReleased(MouseEvent e){

        }
    }

    Hole f1;
    Hole f2;
    Wormhole(int x0, int y0, int x1, int y1){
        try{
        robot = new Robot();
        }catch(AWTException e){}
        f1 = new Hole(x0,y0);
        f2 = new Hole(x1,y1);
        f1.setOther(f2);
        f2.setOther(f1);
        
    }
    public static void main(String[] args){
        int x0 = 1870; try{x0 = Integer.parseInt(args[0]);}catch(Exception e){}
        int y0 = 800;  try{y0 = Integer.parseInt(args[1]);}catch(Exception e){}
        int x1 = 3200; try{x1 = Integer.parseInt(args[2]);}catch(Exception e){}
        int y1 = 800;  try{y1 = Integer.parseInt(args[3]);}catch(Exception e){}
        new Wormhole(x0,y0,x1,y1);
    }
}