Revert "Configure virtual threads on Undertow if enabled"

This reverts commit cff1b33.

See gh-38819

Closes gh-39812

Author: mhalbritter

Diff for: spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/EmbeddedWebServerFactoryCustomizerAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -34,18 +34,15 @@
 import org.springframework.boot.autoconfigure.thread.Threading;
 import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
-import org.springframework.boot.web.embedded.undertow.UndertowDeploymentInfoCustomizer;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
-import org.springframework.core.task.VirtualThreadTaskExecutor;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for embedded servlet and reactive
  * web servers customizations.
  *
  * @author Phillip Webb
- * @author Moritz Halbritter
  * @since 2.0.0
  */
 @AutoConfiguration
@@ -110,12 +107,6 @@ public UndertowWebServerFactoryCustomizer undertowWebServerFactoryCustomizer(Env
 			return new UndertowWebServerFactoryCustomizer(environment, serverProperties);
 		}
 
-		@Bean
-		@ConditionalOnThreading(Threading.VIRTUAL)
-		UndertowDeploymentInfoCustomizer virtualThreadsUndertowDeploymentInfoCustomizer() {
-			return (deploymentInfo) -> deploymentInfo.setExecutor(new VirtualThreadTaskExecutor("undertow-"));
-		}
-
 	}
 
 	/**

Diff for: spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/UndertowWebServerFactoryCustomizer.java

@@ -77,7 +77,8 @@ public int getOrder() {
 	public void customize(ConfigurableUndertowWebServerFactory factory) {
 		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 		ServerOptions options = new ServerOptions(factory);
-		map.from(this.serverProperties::getMaxHttpRequestHeaderSize)
+		ServerProperties properties = this.serverProperties;
+		map.from(properties::getMaxHttpRequestHeaderSize)
 			.asInt(DataSize::toBytes)
 			.when(this::isPositive)
 			.to(options.option(UndertowOptions.MAX_HEADER_SIZE));