使用Java中的KeyEvent类实现不同的修改键组合，例如Shift、Ctrl、Alt等键。

示例代码：

import java.awt.event.KeyEvent;

public class KeyDemo {
    public static void main(String[] args) {
        // 监听键盘事件
        KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {
            @Override
            public boolean dispatchKeyEvent(KeyEvent e) {
                if (e.getID() == KeyEvent.KEY_PRESSED) {
                    // 判断按下的键是否是指定组合键
                    boolean isCtrlPressed = e.isControlDown();
                    boolean isAltPressed = e.isAltDown();
                    boolean isShiftPressed = e.isShiftDown();
                    if (isCtrlPressed && isAltPressed && isShiftPressed) {
                        // 执行操作
                        System.out.println("Ctrl + Alt + Shift 已经按下");
                    }
                }
                return false;
            }
        });
    }
}