求助：关于用Intent传递List<>类型的问题

public class Music implements Serializable {
private static final long serialVersionUID = -7060210544600464481L;

int musicId;
String musicName;
String musicPath;


public int getMusicId() {
return musicId;
}
public void setMusicId(int musicId) {
this.musicId = musicId;
}
public String getMusicName() {
return musicName;
}
public void setMusicName(String musicName) {
this.musicName = musicName;
}
public String getMusicPath() {
return musicPath;
}
public void setMusicPath(String musicPath) {
this.musicPath = musicPath;
}

}






public void searchMusci(File file) {
musicList = new ArrayList<Music>();
File[] files = file.listFiles();
for(int i=0; i<files.length; i++) {
if(files[i].isDirectory()) {
searchMusci(files[i]);
}else if(files[i].getName().endsWith(".mp3")){
music = new Music();
music.setMusicId(i);
music.setMusicName(files[i].getName());
music.setMusicPath(files[i].getAbsolutePath());
musicList.add(music);
}

}

musicList = Collections.synchronizedList(new ArrayList<Music>());//把List类型强转型
Intent intent = new Intent("android.music.MusicService_Action");
intent.putExtras(1, musicList);
}
上面的Music.class已经实现Synchronize接口，但是最后一行intent.putExtra（1, musicList）提示错误，这是为什么呢？有个参考文章链接http://www.eoeandroid.com/forum.php?mod=viewthread&tid=81308 希望大神们指点下