docs: public static void deleteFileOrDir(File file) throws IOException {
  	if (file.isDirectory()) {
  	    File[] children = file.listFiles();
  	    if (children != null) {
  		for (File child : children) {
  		    deleteFileOrDir(child);
  		}
  	    }
  	}
  	if (!file.delete()) {
  	    throw new IOException("Could not remove '" + file + "'!");
  	}
      }