Add class of SslBundleSslEngineFactory to Kafka config map

Closes gh-44414

Author: mhalbritter

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/KafkaProperties.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.
@@ -1455,7 +1455,7 @@ public Map<String, Object> buildProperties(SslBundles sslBundles) {
 
 		private Map<String, Object> buildPropertiesForSslBundle(SslBundles sslBundles, String name) {
 			Properties properties = new Properties();
-			properties.in(SslConfigs.SSL_ENGINE_FACTORY_CLASS_CONFIG).accept(SslBundleSslEngineFactory.class.getName());
+			properties.in(SslConfigs.SSL_ENGINE_FACTORY_CLASS_CONFIG).accept(SslBundleSslEngineFactory.class);
 			properties.in(SslBundle.class.getName()).accept(sslBundles.getBundle(name));
 			return properties;
 		}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/kafka/KafkaPropertiesTests.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.
@@ -108,7 +108,7 @@ void sslBundleConfiguration() {
 		Map<String, Object> consumerProperties = properties
 			.buildConsumerProperties(new DefaultSslBundleRegistry("myBundle", this.sslBundle));
 		assertThat(consumerProperties).containsEntry(SslConfigs.SSL_ENGINE_FACTORY_CLASS_CONFIG,
-				SslBundleSslEngineFactory.class.getName());
+				SslBundleSslEngineFactory.class);
 	}
 
 	@Test