Java program with return value, what is the best way?

Question

I was thinking something like this:
public class A {
public static int intMain(String... argv) {
///real program here
public static void main(String... argv) {
System.exit(intMain(argv));
But System.exit does not await user threads and I use a library which creates threads where I do not have control.
Is there a way to await every user thread without explicitly knowing them?

Answer 1

I just want to return a value to the OS... zero in case of normal quit, non-zero in case of abnormal termination. I do not see anything complex in that. Actually it I think is crazy that Java mains are only void.
About threads I use rabbitmq and it uses threads for its messaging. I noticed the problem because if I forget to correctly close rabbitmq objects the ``void main'' does not terminate while the ``int main'' does since system.exit does not wait.
At the moment the question is more about curiosity, really there is no simple way to say ``await all users threads''?