How can I make the value of the variable be automatically saved when the program ends?

Question

Java

How can I make sure that after the program is closed, the value of the variable is saved, and the next time it is started, the variable already has the same value when the program was last closed?

Answer 1

public class Example {
    private static final String FILE_NAME = "state.dat";

    private int value;

    public void setValue(int value) {
        this.value = value;
    }

    public int getValue() {
        return value;
    }

    public static void main(String[] args) {
        Example obj = new Example();

        try (InputStream in = new FileInputStream(FILE_NAME)) {
            obj.setValue(in.read());
        } catch (IOException exc) {
            exc.printStackTrace();
        }

        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            try (OutputStream out = new FileOutputStream(FILE_NAME)) {
                out.write(obj.getValue());
            } catch (IOException exc) {
                exc.printStackTrace();
            }
        }));
    }
}