GH-3662: Support Kafka 3.9.0+ in EmbeddedKafkaKraftBroker

Fixes: #3662
Issue: #3662

Add compatibility for both Kafka 3.8.0 and 3.9.0+ by handling different method signatures for setConfigProp:
- 3.9.0+: setConfigProp(String, Object)
- 3.8.0: setConfigProp(String, String)

The change uses reflection to detect Kafka version and call appropriate method.

* Direct call to setConfigProp when using 3.8.0

* Addressing PR review

* Addressing PR review

spring-kafka-test/src/main/java/org/springframework/kafka/test/EmbeddedKafkaKraftBroker.java

@@ -18,6 +18,7 @@
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.lang.reflect.Method;
 import java.nio.file.Files;
 import java.time.Duration;
 import java.util.AbstractMap.SimpleEntry;
@@ -56,6 +57,8 @@
 
 import org.springframework.core.log.LogAccessor;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * An embedded Kafka Broker(s) using KRaft.
@@ -87,6 +90,23 @@ public class EmbeddedKafkaKraftBroker implements EmbeddedKafkaBroker {
 
 	public static final int DEFAULT_ADMIN_TIMEOUT = 10;
 
+	private static final boolean IS_KAFKA_39_OR_LATER = ClassUtils.isPresent(
+			"org.apache.kafka.server.config.AbstractKafkaConfig", EmbeddedKafkaKraftBroker.class.getClassLoader());
+
+	private static final Method SET_CONFIG_METHOD;
+
+	static {
+		if (IS_KAFKA_39_OR_LATER) {
+			SET_CONFIG_METHOD = ReflectionUtils.findMethod(
+					KafkaClusterTestKit.Builder.class,
+					"setConfigProp",
+					String.class, Object.class);
+		}
+		else {
+			SET_CONFIG_METHOD = null;
+		}
+	}
+
 	private final int count;
 
 	private final Set<String> topics;
@@ -212,7 +232,7 @@ private void start() {
 							.setNumBrokerNodes(this.count)
 							.setNumControllerNodes(this.count)
 							.build());
-			this.brokerProperties.forEach((k, v) -> clusterBuilder.setConfigProp((String) k, (String) v));
+			this.brokerProperties.forEach((k, v) -> setConfigProperty(clusterBuilder, (String) k, v));
 			this.cluster = clusterBuilder.build();
 		}
 		catch (Exception ex) {
@@ -238,6 +258,17 @@ private void start() {
 		System.setProperty(SPRING_EMBEDDED_KAFKA_BROKERS, getBrokersAsString());
 	}
 
+	private static void setConfigProperty(KafkaClusterTestKit.Builder clusterBuilder, String key, Object value) {
+		if (IS_KAFKA_39_OR_LATER) {
+			// For Kafka 3.9.0+: use reflection
+			ReflectionUtils.invokeMethod(SET_CONFIG_METHOD, clusterBuilder, key, value);
+		}
+		else {
+			// For Kafka 3.8.0: direct call
+			clusterBuilder.setConfigProp(key, (String) value);
+		}
+	}
+
 	@Override
 	public void destroy() {
 		AtomicReference<Throwable> shutdownFailure = new AtomicReference<>();