code: public void addWatchDirectory(File dir, List<String> fileExtensions) {
      	List<String> fileExtensionsWithoutDot = new ArrayList<String>(fileExtensions.size());
      	for(String fileExtension : fileExtensions){
      		fileExtensionsWithoutDot.add(removeStartingDotIfPresent(fileExtension));
      	}
      	directoryWatcherDelegate.addWatchDirectory(dir, fileExtensions);
      }
docs: Adds a directory to watch for the given file and extensions.
  
  @param dir The directory
  @param fileExtensions The extensions