[BAEL-6621] - revert Map.

Author: LordMaduz

spring-reactive-modules/spring-reactive-kafka/src/test/java/com/baeldung/reactive/kafka/ReactorKafkaConsumerUnitTest.java

@@ -3,7 +3,6 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -49,9 +48,7 @@ public class ReactorKafkaConsumerUnitTest {
 
     @BeforeEach
     void setUp() {
-        Map<String, Object> map = new HashMap<>();
-        map.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
-        kafkaAdmin = new KafkaAdmin(map);
+        kafkaAdmin = new KafkaAdmin(Map.of(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers));
     }
 
     @AfterEach