code: public static Runnable watch(Path path, PathEventListener listener) throws IOException {
  		return watch(path, listener,
  			StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY);
  	}
docs: Watch the given path.
  This will launch the thread if not yet launched.
  The returned Runnable can be called to stop watching.