Fail fast when trying to use SNI with reactive Jetty

Previously only a servlet-based Jetty server would fail fast when
trying to use SNI with Jetty. A reactive Jetty server just ignored
the configuration. This commit aligns the behavior of the two by
making the reactive server fail fast as well.

Closes gh-44316

Author: wilkinsona

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyReactiveWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -249,6 +249,7 @@ private Handler applyWrapper(Handler handler, Handler.Wrapper wrapper) {
 	}
 
 	private void customizeSsl(Server server, InetSocketAddress address) {
+		Assert.state(getSsl().getServerNameBundles().isEmpty(), "Server name SSL bundles are not supported with Jetty");
 		new SslServerCustomizer(getHttp2(), address, getSsl().getClientAuth(), getSslBundle()).customize(server);
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/JettyReactiveWebServerFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -20,6 +20,7 @@
 import java.net.InetAddress;
 import java.time.Duration;
 import java.util.Arrays;
+import java.util.List;
 
 import org.awaitility.Awaitility;
 import org.eclipse.jetty.server.ConnectionLimit;
@@ -33,11 +34,14 @@
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
 import org.springframework.boot.web.server.Shutdown;
+import org.springframework.boot.web.server.Ssl;
+import org.springframework.boot.web.server.Ssl.ServerNameSslBundle;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.web.reactive.function.client.WebClient;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
@@ -146,6 +150,19 @@ void shouldApplyMaxConnections() {
 		assertThat(connectionLimit.getMaxConnections()).isOne();
 	}
 
+	@Test
+	void sslServerNameBundlesConfigurationThrowsException() {
+		Ssl ssl = new Ssl();
+		ssl.setBundle("test");
+		List<ServerNameSslBundle> bundles = List.of(new ServerNameSslBundle("first", "test1"),
+				new ServerNameSslBundle("second", "test2"));
+		ssl.setServerNameBundles(bundles);
+		JettyReactiveWebServerFactory factory = getFactory();
+		factory.setSsl(ssl);
+		assertThatIllegalStateException().isThrownBy(() -> this.webServer = factory.getWebServer(new EchoHandler()))
+			.withMessageContaining("Server name SSL bundles are not supported with Jetty");
+	}
+
 	@Override
 	protected String startedLogMessage() {
 		return ((JettyWebServer) this.webServer).getStartedLogMessage();