Use Java Native Access to Determine Default Directory

Context and Problem Statement

JabRef needs to propose a file directory to a user for storing files. How to determine the “best” directory native for the OS the user runs.

Chosen option: “Java Native Access”, because comes out best (see below).

Swing’s FileChooser implemented a very decent directory determination algorithm. It thereby uses sun.awt.shell.ShellFolder.

Good, because provides best results on most platforms.
Good, because also supports localization of the folder name. E.g., ~/Dokumente in Germany.
Bad, because introduces a dependency on Swing and thereby contradicts the second decision driver.
Bad, because GraalVM’s support Swing is experimental.
Bad, because handles localization only on Windows.

There is System.getProperty("user.home");.

Bad, because “The concept of a HOME directory seems to be a bit vague when it comes to Windows”. See https://stackoverflow.com/a/586917/873282 for details.
Bad, because it does not include Documents: As of 2022, System.getProperty("user.home") returns c:\Users\USERNAME on Windows 10, whereas FileSystemView returns C:\Users\USERNAME\Documents, which is the “better” directory.

AppDirs is a small java library which provides a path to the platform dependent special folder/directory.

Good, because already used in JabRef.
Bad, because does not use Documents on Windows, but rather C:\Users\<Account>\AppData\<AppAuthor>\<AppName> as basis.

Good, because no additional dependency required, as it is already loaded by AppDirs.
Good, because it is well maintained and widely used.
Good, because it provides direct access to Documents and other system variables.