Where to store data between runs in Java

Question

I am using ObjectOutputStream and ObjectInputStream to read and write data that needs to be stored in between program runs. My question is if there is a proper place to create these files. At the moment I use the following code to find the user's Documents folder.

String myDocuments = null;

        try {
            Process p = Runtime.getRuntime()
                    .exec("reg query \"HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders\" /v personal");
            p.waitFor();

            InputStream in = p.getInputStream();
            byte[] b = new byte[in.available()];
            if (in.read(b) == 0) myDocuments = JOptionPane.showInputDialog(this,
                    "A fatal error has occurred. \n Please provide your documents folder.");
            else {

                myDocuments = new String(b);
                myDocuments = myDocuments.split("\\s\\s+")[4];
            }
            in.close();

            Log.logLine(myDocuments);

        } catch (Throwable t) {
            t.printStackTrace();
        }

Is this okay as a practice, and if not where should I be storing this information? Also is there a way to do this while still allowing for the application to run a different OS as I am aware that the current method only works with Windows OS.

You could use the temp folder if it's nice, but not required, to have this data available in the next run. — Lino, Jun 16 '21 at 10:34
The program is meant to work for long periods of time between syncing with a central database. It really needs to have the data persist. — Parzavil, Jun 16 '21 at 10:35
Related: https://stackoverflow.com/questions/11113974/what-is-the-cross-platform-way-of-obtaining-the-path-to-the-local-application-da — Turamarth, Jun 16 '21 at 10:46

score 1 · Accepted Answer · edited Jun 16 '21 at 10:56

1

I guess it depends on your requirements. Something that should work on every(?) OS is using the application's own folder (or a sub folder of that):

String dir = System.getProperty("user.dir");

edited Jun 16 '21 at 10:56

Federico klez Culloca

24,336
15
57
93

answered Jun 16 '21 at 10:45

reden

942
6
14

3

`String dir = System.getProperty("user.dir");` is probably shorter and more explicit. – Olivier Grégoire Jun 16 '21 at 10:49

Where to store data between runs in Java

1 Answers1