Upgrade to Tomcat 10.1.9

Closes gh-35819

gradle.properties

@@ -7,6 +7,6 @@ org.gradle.jvmargs=-Xmx2g -Dfile.encoding=UTF-8
 kotlinVersion=1.8.22
 nativeBuildToolsVersion=0.9.22
 springFrameworkVersion=6.0.10-SNAPSHOT
-tomcatVersion=10.1.8
+tomcatVersion=10.1.9
 
 kotlin.stdlib.default.dependency=false

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -475,6 +475,7 @@ public class ServerProperties {
 		/**
 		 * Whether to reject requests with illegal header names or values.
 		 */
+		@Deprecated(since = "2.7.12", forRemoval = true)
 		private boolean rejectIllegalHeader = true;
 
 		/**
@@ -633,6 +634,7 @@ public class ServerProperties {
 			this.connectionTimeout = connectionTimeout;
 		}
 
+		@DeprecatedConfigurationProperty(reason = "The setting has been deprecated in Tomcat")
 		public boolean isRejectIllegalHeader() {
 			return this.rejectIllegalHeader;
 		}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizer.java

@@ -198,6 +198,7 @@ public class TomcatWebServerFactoryCustomizer
 		factory.addConnectorCustomizers((connector) -> connector.setProperty("relaxedQueryChars", relaxedChars));
 	}
 
+	@SuppressWarnings("deprecation")
 	private void customizeRejectIllegalHeader(ConfigurableTomcatWebServerFactory factory, boolean rejectIllegalHeader) {
 		factory.addConnectorCustomizers((connector) -> {
 			ProtocolHandler handler = connector.getProtocolHandler();

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizerTests.java

@@ -437,6 +437,7 @@ class TomcatWebServerFactoryCustomizerTests {
 	}
 
 	@Test
+	@Deprecated(since = "2.7.12", forRemoval = true)
 	void testCustomizeRejectIllegalHeader() {
 		bind("server.tomcat.reject-illegal-header=false");
 		customizeAndRunServer((server) -> assertThat(