How to shut down all Executors when quitting an application?

Question

According to Brian Goetz\'s Java Concurrency in Practice JVM can\'t exit until all the (nondaemon) threads have terminated, so failing to shut down an Executor could pre

Answer 1

Decorate the executor with com.google.common.util.concurrent.MoreExecutors#getExitingExecutorService

@Beta
public static ExecutorService getExitingExecutorService(ThreadPoolExecutor executor,
                                         long terminationTimeout,
                                         TimeUnit timeUnit)

Converts the given ThreadPoolExecutor into an ExecutorService that exits when the application is complete. It does so by using daemon threads and adding a shutdown hook to wait for their completion.

This is mainly for fixed thread pools. See Executors.newFixedThreadPool(int).