What is the output when the program is executed?

public class RecursiveReturn {
    public static int recursiveSum(int n) {
        if(n <= 0) return 0;
        Thread t = new Thread(() -> {});
        t.start();
        try {
            t.join();
        } catch(InterruptedException e) {
            Thread.currentThread().interrupt();
        }
        return n + recursiveSum(n - 1);
    }
    
    public static void main(String[] args) {
        System.out.println(recursiveSum(3));
    }
}