How to check file permissions in Java (OS independently)

Question

I have the following snippet of code:

public class ExampleClass {

public static void main(String[] args) throws FileNotFoundException {
    String filePath = args[0];
    File file = new File(filePath);

    if (!file.exists())
        throw new FileNotFoundException();

    if (file.canWrite())
        System.out.println(file.getAbsolutePath() + ": CAN WRITE!!!");
    else
        System.out.println(file.getAbsolutePath() + ": CANNOT WRITE!!!!!");

    if (file.canRead())
        System.out.println(file.getAbsolutePath() + ": CAN READ!!!");
    else
        System.out.println(file.getAbsolutePath() + ": CANNOT READ!!!!!");

    if (file.canExecute())
        System.out.println(file.getAbsolutePath() + ": CAN EXECUTE!!!");
    else
        System.out.println(file.getAbsolutePath() + ": CANNOT EXECUTE!!!!!");
}
}

It works in Linux OS, but the problem is that it doesn't work in windows7. So the question is: Does anybody know a method to check privileges to a file in Java OS INDEPENDENTLY?

Answer 1

This might be caused by something (for instance an anti-virus product) "mediating" file access in an inconsistent way.

Certainly, it is hard to believe that the Java File.canXxxx() methods are generally broken on any flavour of Windows.

---

UPDATE - I take that back. Read this Sun bug report ... and weep. The short answer is that it is a Windows bug, and Sun decided not to work around it. (But the new Java 7 APIs do work ...)

FWIW, I maintain that it is BAD PRACTICE to try to check file access permissions like that. It is better to simply attempt to use the file, and catch the exceptions if / when they occur. See https://stackoverflow.com/a/6093037/139985 for my reasoning. (And now we have another reason ...)