diff --git a/spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java b/spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java
index eb8edc0e98c..e3a3e2ff4a4 100644
--- a/spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java
+++ b/spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java
@@ -405,8 +405,8 @@ public class UndertowEmbeddedServletContainerFactory
 
 	private XnioWorker createWorker() throws IOException {
 		Xnio xnio = Xnio.getInstance(Undertow.class.getClassLoader());
-		OptionMap.Builder builder = OptionMap.builder();
-		return xnio.createWorker(builder.getMap());
+		return xnio.createWorker(
+				OptionMap.builder().set(Options.THREAD_DAEMON, true).getMap());
 	}
 
 	private void registerServletContainerInitializerToDriveServletContextInitializers(