How Do You Stop a Java Program Gracefully?
This short article provides readers with a way to gracefully stop a Java program in case your program may be doing something important.
CORE
·
Sometimes you may want to stop your java program using SIGINT hitting your CTRL+C. For example, your program may be doing something important, e.g., opening a server socket and waiting on a port or doing some background work on a thread pool. You want to stop it gracefully, shutting down your socket or the thread pool. For such scenarios, what you can do is add a shutdown hook to the java runtime. The following code demonstrates precisely that:
package com.bazlur;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class Day008 {
public static void main(String[] args) {
var executorService = Executors.newSingleThreadExecutor();
executorService.submit((Runnable) () -> {
while (true) {
doingAStupendousJob();
}
});
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
try {
executorService.shutdown();
if (executorService.awaitTermination(100, TimeUnit.MILLISECONDS)) {
System.out.println("Still waiting 100ms...");
executorService.shutdownNow();
}
System.out.println("System exited gracefully");
} catch (InterruptedException e) {
executorService.shutdownNow();
}
}));
}
private static void doingAStupendousJob() {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}Published at DZone with permission of A N M Bazlur Rahman. See the original article here.
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