In Java, what do the periods in this File location denote?

Question

I'm looking at some sample code for creating a File in Java:

File f = new File("test/.././file.txt");

I'm confused at how this works - how can you have "test" , and then those .. and . in between like that? If I run this code in an arbitrary directory in my machine, why does it work(i.e I don't have a folder called "test" ).

this is part of some code for Path-Testing in java(getAbsolutePath() and etc)

thanks

Answer 1

the .. denote a parent directory; . denote this directory.

Having this as valid is another good reason why you should use getCanonicalPath() vs getAbsolutePath()

For example: Lets say your file is under /folder1/folder2 directory

then

File f = new File("/folder1/folder2/folder3/../<your file>");
f.getCanonicalPath() ==> /folder1/folder2/<your file>
f.getAbsolutePath() ==> /folder1/folder2/folder3/../<your file>

Answer 2

The .. just means "up a directory level". The single . just means "current directory level". Why they are in your file path is beyond me. Your path seems to mean "go into the test folder, then go up a level (to the one you started in), stay in that level, then look for file.txt". You could do the same thing with just new File("file.txt").

Answer 3

File f = new File("test/.././file.txt");  //.. is used to go one hierarchy above in the directory structure and . is for current directory

suppose you have directory structure like ABC/test/file.txt and if you are inside test then your . is path upto test and .. is path upto ABC as .. represents parent directory and parent of "test" is "ABC"

Answer 4

Because the .. goes back up the directory hierarchy, so you'll be back to where you started (not in test). This is unnecessary as it's equivalent to:

File("test.txt")

And so should work regardless of which directory you run it in.

Answer 5

The ".." will go up one directory from the current directory. So, this code is basically the same as new File("./file.txt");

Answer 6

./ goes to the directory where your project is located ../ Goes back a folder lets say you have a resource directory

Res/graphics/sprites/image.png

If you do File file = new File("./graphics/sprites/); That will point to the sprites directory

Now if you want to go back a file dir File newFile = file + "../";