if (f1.isDirectory() && f2.isFile())
if (f1.isDirectory() && !f2.isDirectory())
    public int compare(Object o1, Object o2) {        if (o1 == null)            return 1;        if (o2 == null)            return -1;        File f1 = (File) o1;        File f2 = (File) o2;        // Les rpertoires, toujours en premier        if (f1.isDirectory() && f2.isFile())            return -1;        if (f1.isFile() && f2.isDirectory())            return 1;        return Collator.getInstance().compare(f1.getName(), f2.getName());    }