Java Keylistener没有窗口打开？

import java.awt.*;
import java.awt.event.*;

public class KeyListenerExample {
    public static void main(String[] args) {
        // 创建一个隐藏的窗口
        Frame frame = new Frame();
        frame.setUndecorated(true);
        frame.setVisible(true);
        frame.setSize(0, 0);

        // 添加KeyListener到窗口上
        frame.addKeyListener(new KeyAdapter() {
            public void keyPressed(KeyEvent e) {
                System.out.println("Key pressed: " + KeyEvent.getKeyText(e.getKeyCode()));
            }

            public void keyReleased(KeyEvent e) {
                System.out.println("Key released: " + KeyEvent.getKeyText(e.getKeyCode()));
            }

            public void keyTyped(KeyEvent e) {
                System.out.println("Key typed: " + e.getKeyChar());
            }
        });
    }
}