以下是Java操作Windows系统功能的几个案例：

1. 打开系统默认浏览器：

Desktop.getDesktop().browse(URI.create("http://www.google.com"));

1. 打开文件夹：

FileManager fileManager = new FileManager();
fileManager.openFolder("C:\\Users");

public class FileManager {
    public void openFolder(String path) {
        try {
            Runtime.getRuntime().exec("explorer.exe /select,"+path);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

1. 播放音频：

MediaPlayer mediaPlayer = new MediaPlayer(new Media(new File("E:/music.mp3").toURI().toString()));
mediaPlayer.play();

public class MediaPlayer {
    private final Media media;
    private final javafx.scene.media.MediaPlayer player;

    public MediaPlayer(Media media) {
        this.media = media;
        player = new javafx.scene.media.MediaPlayer(media);
    }

    public void play() {
        player.play();
    }

    public void pause() {
        player.pause();
    }

    public void stop() {
        player.stop();
    }
}

1. 打开命令行并执行命令：

CMD.execute("cmd /c dir");

public class CMD {
    public static void execute(String command) {
        try {
            Process process = Runtime.getRuntime().exec(command);
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}