Java nio: How to add extension to an absolute path?

Question

This feels like it should be something straight forward, but I can seem to find an elegant solution to it without converting to File.

Given a Path

Path path = Paths.get("/a/b/foo") 

How to do get the path /a/b/foo.bar? subpath will return a relative path regardless of whether the original path is relative or absolute.

I would prefer not to have to use additional libraries. But, maybe that is the only way?

Answer 1

To change the file name of a Path, use one of the resolveSibling() methods:

This is useful where a file name needs to be replaced with another file name.

Using this method ensures that the result Path object is for the same FileSystem as the source Path object.

So, to add extension ".bar" to a Path:

path = path.resolveSibling(path.getFileName() + ".bar");