FULL PRODUCT VERSION :
java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
NTFS filesystem

A DESCRIPTION OF THE PROBLEM :
When obtaining a list of files on "C:/", the listFiles() method returns files which, when exists() is called, returns false.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
This is noticeable on the hiberfil.sys file on the root of C:. If you don't have this file, you probably won't be able to reproduce the problem unless you find a file which behaves similarly.

Compile and run the provided sample program.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The program should show "exists" next to every file in the list.

ACTUAL -
The file "C:\hiberfil.sys" says "DOES NOT EXIST", as File.exists() returned false for that file, despite it having been returned in File.listFiles()

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class Test {
    public static void main (String args[]) {
        File root = new File("C:\\");
        System.out.println("Root is " + root);

        File[] dir = root.listFiles();
        for (int i = 0; i < dir.length; i++) {
            System.out.print(" dir[" + i + "] = " + dir[i] + " ");
            if (dir[i].exists()) {
                System.out.println("exists");
            } else {
                System.out.println("DOES NOT EXIST!");
            }
        }
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
It's ugly, but there are two options.

Option one, have a way to return a File array which is already sanitised:

public static File[] listFilesFixed(File parent) {
    File[] list = parent.listFiles();
    List fixedList = new ArrayList();
    for (int i = 0; i < list.length; i++) {
        if (list[i].exists()) {
            fixedList.add(list[i]);
        }
    }
    return (File[]) fixedList.toArray(new File[fixedList.size()]);
}

Option two is to take the result of listFiles() with a shaker of salt, and check exists() on every single file in the list.
###@###.### 2004-11-08 21:08:40 GMT