Is there a way to dynamically restart a HelloWorld Java program which loops print outputs?

Question

Consider the following simple code that prints "Hi world" forever:

public class WakeMeUpSomehow {

 public static void main(String[] args) {

    while (true) {
    try {
         System.out.println( " Hi world ");
         Thread.sleep(1000);                 //1000 milliseconds is one second.
    } catch(InterruptedException ex) {
         Thread.currentThread().interrupt();
    }
    }
 }
}

Here is the output:

Is there a way to devise an external third program , which watches this program to notice when we kill it (like with CTRL+C in command line); and then this "parent" program resumes the "Hello World" running ?

I think it might look something like this :

So my question is - how can I simulate code like this, which has this kind of fail-safe ability? Is there an way to do this?

thanks !

EDIT: I found a neat link here which is relevant but addresses something a little different- How can I restart a Java application?

Answer 1

Shutdown hooks are guaranteed to run on normal shutdown events of a program, but not on all kinds of abnormal termination, such as when the JVM is killed forcibly.

One solution may be to use a batch script:

@echo off
setlocal

start /wait java WakeMeUpSomehow

if errorlevel 1 goto retry
echo Finished successfully
exit

:retry
echo retrying...
start /wait java WakeMeUpSomehow

Answer 2

If it's as simple as this, you can simply use a shutdownhook.

Runtime.getRuntime().addShutdownHook(() -> {
    //do whatever you want to be done when closing the program here
});

Though you might encounter some problems, if you want to restart the program and use the same commandline.