Difference between Files#delete(Path) and File#del

问题:

I'm using Windows-7 with java 7 update 6 and found this weird (at least to me) behavior -
I have two files E:\delete1.txt and E:\delete2.txt both are read only files, when I try to delete file like following it gets deleted without any issues -

File file = new File("E:\\delete1.txt"); 
assertTrue(file.delete());

But when I delete file using nio API like following -

Path path = Paths.get("E:\\delete2.txt");
Files.delete(path);

It throws java.nio.file.AccessDeniedException.

Why different behavior for same operation with old and new nio API?

回答1:

As discussed here - The issue is that java.io.File has many oddities, on Windows in particular. In this case it resets the file attributes before it deletes the file so this is why it does not fail as might be expected. It is behavior that dates back >10 years and so would be risky to change now. It has several other oddities like this, just one of the reason why it wasn't re-implemented to use the new API.

If we try to delete the file from command window then windows throws the same (Access denied) error but file gets deleted from explorer window. It appears the File#delete() has a wrong implementation and new Files#delete(Path) should be preferred instead.

回答2:

Why different behavior for same operation with old and new nio API?

Because exactly emulating the behaviour of the old API for similar operations was apparently not considered an important goal in the design of the new API. Given that the main goal of the nio filesystem API was to present a new API with some quite different underlying concepts and a lot of new capabilities, it seems pretty normal to me.