(fs) Files.move does not throw DirectoryNotEmptyException when source is non-empty

“ DirectoryNotEmptyException - the REPLACE_EXISTING option is specified but the file cannot be replaced because it is a non-empty directory, or the source is a non-empty directory containing entries that would be required to be moved”

Observation :
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When the code tries to move the file from a source to a non-empty target the desired exception is thrown.
But when the source is non-empty directory but target is empty directory the desired exception is not thrown, As I understand it should throw the desired exception in this case too?

Platform : Windows, Linux
JDK used : JDK-15 (ea -26)

Please find the attached code snippet, where “source” directory is non –empty but the “target5” is empty.

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public class MoveFilesTest {

    public static void main(String[] args)
    {
        new MoveFilesTest().runtTest();
    }

    private void runtTest() {

        Path path = Paths.get("/scratch/kganapur").resolve("source");
        Path path1 = Paths.get("/scratch/kganapur").resolve("target5");

        try {
            System.out.println("The paths are " + path + " " + path1);
            Files.move(path, path1, StandardCopyOption.REPLACE_EXISTING);
            System.out.println("FAILED: DirectoryNotEmptyException was NOT " +
                    "thrown");
        } catch (DirectoryNotEmptyException expected) {
            System.out.println("expected DNEmpty Ex ");
        } catch (IOException ioe) {
            // permissible in place of DirectoryNotEmptyException
            System.out.println("WARNING: " + ioe);
        }
        System.out.println("OKAY");
    }
}