The default executor service of java.io.concurrent.Future creates dae…

…mon threads

vavr/src/main/java/io/vavr/concurrent/Future.java

@@ -58,10 +58,14 @@
 public interface Future<T> extends Value<T> {
 
     /**
-     * The default executor service is {@link Executors#newCachedThreadPool()}.
-     * Please note that it may prevent the VM from shutdown.
-     */
-    ExecutorService DEFAULT_EXECUTOR_SERVICE = Executors.newCachedThreadPool();
+     * The default executor service is {@link Executors#newCachedThreadPool()}. The service will create daemon threads,
+     * in order to avoid preventing the VM from shutdown.
+     */
+    ExecutorService DEFAULT_EXECUTOR_SERVICE = Executors.newCachedThreadPool(runnable -> {
+        Thread thread = Executors.defaultThreadFactory().newThread(runnable);
+        thread.setDaemon(true);
+        return thread;
+    });
 
     /**
      * Creates a failed {@code Future} with the given {@code exception}, backed by the {@link #DEFAULT_EXECUTOR_SERVICE}.