Merge branch '2.1.x' into 2.2.x

Closes gh-20499

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactory.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -131,7 +131,7 @@ public class TomcatReactiveWebServerFactory extends AbstractReactiveWebServerFac
 		}
 		TomcatHttpHandlerAdapter servlet = new TomcatHttpHandlerAdapter(httpHandler);
 		prepareContext(tomcat.getHost(), servlet);
-		return new TomcatWebServer(tomcat, getPort() >= 0);
+		return getTomcatWebServer(tomcat);
 	}
 
 	private void configureEngine(Engine engine) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactoryTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@ import java.net.InetSocketAddress;
 import java.net.ServerSocket;
 import java.util.Arrays;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.catalina.Context;
 import org.apache.catalina.LifecycleEvent;
@@ -256,6 +257,21 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 				.isInstanceOf(WebServerException.class);
 	}
 
+	@Test
+	void whenGetTomcatWebServerIsOverriddenThenWebServerCreationCanBeCustomized() {
+		AtomicReference<TomcatWebServer> webServerReference = new AtomicReference<>();
+		TomcatWebServer webServer = (TomcatWebServer) new TomcatReactiveWebServerFactory() {
+
+			@Override
+			protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {
+				webServerReference.set(new TomcatWebServer(tomcat));
+				return webServerReference.get();
+			}
+
+		}.getWebServer(new EchoHandler());
+		assertThat(webServerReference).hasValue(webServer);
+	}
+
 	private void doWithBlockedPort(BlockedPortAction action) throws IOException {
 		int port = SocketUtils.findAvailableTcpPort(40000);
 		ServerSocket serverSocket = new ServerSocket();