FileObserver Instance Collects Garbage

I need to track all the files in a folder when a file is open (FileObserver.OPEN). I want to execute a method. The problem is several times, an instance of FileObserver is going to GC, I tried this:

    final MyFileObserver fo = new MyFileObserver("/mnt/sdcard/Musicas");
    threadFileObserver = new Runnable() {
        @Override
        public void run() {
            fo.startWatching();
        }
    };
    t = new Thread(threadFileObserver);
    t.run();

But going. The question is, what is the best solution for an instance of FileObserver not going to?

Tks !!!