code: @Deprecated
      public void startWatching(File file) {
          if (file == null) {
              throw new IllegalArgumentException("Null file argument");
          }
          synchronized (mutex) {
              startWatchingInternal(file.toPath());
          }
      }
docs: Start watching a specific file. Note that this will watch the
  file as seen in the directory as it is pointed to. This means that
  if the file itself is a symlink, then change events will notify
  changes to the symlink definition, not the content of the file.
  
  @param file The file to be watched.
  @deprecated Use {@link #addWatcher(File, Listener)} or {@link #weakAddWatcher(File, Listener)}