How to write to a file in a jar-nickname from a class located in the same jar-nickname?

Question

Java

Hello. Faced a problem. Wrote a simple console game. Made a top list of players there. I save the table itself in a TreeSet (where each row is an object with its own fields-columns of the table). Then I serialize this table to a file. When the game starts, the table of players is loaded from the file (deserialization occurs). When I specify this path:

"." + File.separator + "src" + File.separator + TopList.class.getPackage().getName().replace(".", File.separator) + File.separator + "TopListOfPlayers.dat";

then everything works in IDEA, but nothing works in jar-nickname. When I use a resource and do this:

private static final String fileTopList = File.separator +
            TopList.class.getPackage().getName().replace(".", File.separator) +
            File.separator + "TopListOfPlayers.dat";
    private final URL urlFileTopList = getClass().getResource(fileTopList); 
...
try (ObjectInputStream objectInput = new ObjectInputStream(urlFileTopList.openStream())) {
            topList = (Set<TopListEntry>) objectInput.readObject();
        }

It works everywhere (both in jar-nik and in IDEA), but if I use resource loading, I can't write to them. How can this problem be solved? Is it really only working with an external file (outside the jar-nickname)?

Answer 1

Make it easier.
Keep the starting top list in the jar file with the game. When you first need to write to it - create in a strictly defined place (in the user's home directory, next to the jar'nickname, etc) a file with an updated top of the players.
The process of loading the top will look quite simple:
1) Check for the presence of a file with the top players in the selected location.
2) If not found - load from jar file.
And yes - why do you need top players? If you want players from different places to measure the strength of the heroic - you need to store this top centrally - for example, on a single server. If the storage is strictly local - generate a fictitious top at the first start next to the jar file and update as the games progress.

Answer 2

Until I found this: link . And apparently it's impossible. You can only write to some external file. This is inconvenient, because it is easier to distribute the program as a single jar file. The way out is to pack a folder with a jar-nickname and an external file into an archive, and distribute the program in this form. (In my case, I can simply create a top-list file every time in the same folder where the jar-nick is located, and work with this created file.)
PS I just don’t understand yet how to work with the file from the IDEA then, think....