Can strange paths cause a wrong structure of the file system?

Question

Consider the following example:

//both files are the same
final File path = new File("/home/alice/../bob/file.txt");
final File canonicalPath = new File("/home/bob/file.txt");

File parent = canonicalPath;
while((parent = parent.getParentFile()) != null) {
    System.out.println(parent.getName());
}

This would print:

bob
home

If I would use path instead of canonicalPath, would the output be the same or would it be:

bob
home
alice
home

This woule be very strange because it would suggest that alice is the parent of home which is not true.

Answer 1

First of all, I think you want to compare home/alice/../bob/file.txt without a starting / instead of /home/alice/../bob/file.txt, otherwise you'd be comparing apples with oranges.

Actually it's more interesting to compare the difference using this code instead:

    File parent;

    parent = path;
    while((parent = parent.getParentFile()) != null) {
        System.out.println(parent);
    }

    parent = canonicalPath;
    while((parent = parent.getParentFile()) != null) {
        System.out.println(parent);
    }

The parents of "home/alice/../bob/file.txt":

• "home/alice/../bob"
• "home/alice/.."
• "home/alice"
• "home"
• null

In contrast, the parents of "home/bob/file.txt":

• "home/bob"
• "home"
• null