[JAVA-15471] Changed custom properties with spring properties (#13003)

Co-authored-by: panagiotiskakos <panagiotis.kakos@libra-is.com>

spring-kafka/src/main/java/com/baeldung/countingmessages/KafkaCountingMessagesComponent.java

@@ -17,7 +17,7 @@ import java.util.stream.Collectors;
 
 @Component
 public class KafkaCountingMessagesComponent {
-    @Value(value = "${kafka.bootstrapAddress}")
+    @Value(value = "${spring.kafka.bootstrap-servers}")
     private String bootstrapAddress;
 
     public static Map<String, Object> props = new HashMap<>();

spring-kafka/src/main/java/com/baeldung/spring/kafka/KafkaConsumerConfig.java

@@ -22,7 +22,7 @@ import org.springframework.kafka.support.serializer.JsonDeserializer;
 @Configuration
 public class KafkaConsumerConfig {
 
-    @Value(value = "${kafka.bootstrapAddress}")
+    @Value(value = "${spring.kafka.bootstrap-servers}")
     private String bootstrapAddress;
 
     public ConsumerFactory<String, String> consumerFactory(String groupId) {

spring-kafka/src/main/java/com/baeldung/spring/kafka/KafkaProducerConfig.java

@@ -16,7 +16,7 @@ import org.springframework.kafka.support.serializer.JsonSerializer;
 @Configuration
 public class KafkaProducerConfig {
 
-    @Value(value = "${kafka.bootstrapAddress}")
+    @Value(value = "${spring.kafka.bootstrap-servers}")
     private String bootstrapAddress;
 
     @Bean

spring-kafka/src/main/java/com/baeldung/spring/kafka/KafkaTopicConfig.java

@@ -13,7 +13,7 @@ import org.springframework.kafka.core.KafkaAdmin;
 @Configuration
 public class KafkaTopicConfig {
 
-    @Value(value = "${kafka.bootstrapAddress}")
+    @Value(value = "${spring.kafka.bootstrap-servers}")
     private String bootstrapAddress;
 
     @Value(value = "${message.topic.name}")

spring-kafka/src/main/resources/application.properties

@@ -1,4 +1,4 @@
-kafka.bootstrapAddress=localhost:9092
+spring.kafka.bootstrap-servers=localhost:9092
 message.topic.name=baeldung
 long.message.topic.name=longMessage
 greeting.topic.name=greeting