watch service does not detect more than one poll java

1Path pathBattlesFolder = Paths.get("filepath");
2WatchService watchService = pathBattlesFolder.getFileSystem().newWatchService();
3pathBattlesFolder.register(watchService, StandardWatchEventKinds.ENTRY_MODIFY);
4WatchKey watchKey = null;
5while(true){
6
7  watchKey = watchService.poll();
8  if (watchKey != null){
9    if (watchKey.pollEvents().size() > 0){
10      //if it gets here then something has been changed
11    }
12    watchKey.reset();
13  }
14
15}
16
17**watchKey.reset() should fix the problem.