A DESCRIPTION OF THE PROBLEM :
Hello. Please review the tutorials under https://docs.oracle.com/javase/tutorial/ - they are not necessarily accurate.

The example: https://docs.oracle.com/javase/tutorial/essential/io/copy.html: "If the target is a non-empty directory, the copy fails with the FileAlreadyExistsException exception." - this does not make sense and is also not true. The exception is DirectoryNotEmptyException.

I'm not sure if this is a good place to report such a mistakes, please let me know.