Fix updateCopyrights Gradle task to read in UTF-8

It looks like `file.text` in Groovy relies on a default charset from operating system.
It causes non-ASCII (e.g. in the `@author`) symbols to be broken

* Make some modification to the `KafkaTemplate` to ensure that copyright is updated, but `Thomas Strauß`
name is not broken

build.gradle

@@ -218,7 +218,7 @@ configure(javaProjects) { subproject ->
 							def beginningYear = matcher[0][1]
 							if (now != beginningYear && now != matcher[0][2]) {
 								def years = "$beginningYear-$now"
-								def sourceCode = file.text
+								def sourceCode = file.getText('UTF-8')
 								sourceCode = sourceCode.replaceFirst(/20\d\d(-20\d\d)?/, years)
 								file.write(sourceCode)
 								println "Copyright updated for file: $file"

spring-kafka/src/main/java/org/springframework/kafka/core/KafkaTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2023 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -79,6 +79,7 @@
 import org.springframework.messaging.converter.SmartMessageConverter;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationRegistry;
@@ -102,7 +103,6 @@
  * @author Soby Chacko
  * @author Gurps Bassi
  */
-@SuppressWarnings("deprecation")
 public class KafkaTemplate<K, V> implements KafkaOperations<K, V>, ApplicationContextAware, BeanNameAware,
 		ApplicationListener<ContextStoppedEvent>, DisposableBean, SmartInitializingSingleton {
 
@@ -226,7 +226,7 @@ public KafkaTemplate(ProducerFactory<K, V> producerFactory, boolean autoFlush,
 		Assert.notNull(producerFactory, "'producerFactory' cannot be null");
 		this.autoFlush = autoFlush;
 		this.micrometerEnabled = KafkaUtils.MICROMETER_PRESENT;
-		this.customProducerFactory = configOverrides != null && configOverrides.size() > 0;
+		this.customProducerFactory = !CollectionUtils.isEmpty(configOverrides);
 		if (this.customProducerFactory) {
 			this.producerFactory = producerFactory.copyWithConfigurationOverride(configOverrides);
 		}
@@ -352,7 +352,7 @@ public boolean isAllowNonTransactional() {
 	}
 
 	/**
-	 * Set to false to disable micrometer timers, if micrometer is on the class path.
+	 * Set to {@code false} to disable micrometer timers, if micrometer is on the class path.
 	 * @param micrometerEnabled false to disable.
 	 * @since 2.5
 	 */
@@ -365,7 +365,7 @@ public void setMicrometerEnabled(boolean micrometerEnabled) {
 	 * @param tags the tags.
 	 * @since 2.5
 	 */
-	public void setMicrometerTags(Map<String, String> tags) {
+	public void setMicrometerTags(@Nullable Map<String, String> tags) {
 		if (tags != null) {
 			this.micrometerTags.putAll(tags);
 		}