The point is that there is no official way to fsync a directory in Java and that everyone is relying on an unintentional side effect of an unrelated function to

The point is that there is no official way to fsync a directory in Java and that everyone is relying on an unintentional side effect of an unrelated function to accomplish it. The link I supplied is about the fact that the side effect briefly disappeared in Java 9 until enough people complained. We're still living in xkcd 1172 land with this, have been for a decade or who knows how long.