GH-248 - Support to automatically externalize events.

We now allow externalizing application events to a variety of message brokers through the addition of Spring Modulith modules for Kafka, AMQP and JMS to a user project's classpath. Which events shall be externalized and how they're supposed to be routed to the message broker can be configured through either annotations or via a configuration API declared as Spring bean.

In case Jackson is on the classpath, we also add auto-configuration to use a Boot-configured ObjectMapper instance with the corresponding message broker client APIs to properly serialize and deserialize messages to JSON.

spring-modulith-examples/spring-modulith-example-kafka/pom.xml

@@ -0,0 +1,52 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<parent>
+		<groupId>org.springframework.modulith</groupId>
+		<artifactId>spring-modulith-examples</artifactId>
+		<version>1.1.0-SNAPSHOT</version>
+	</parent>
+
+	<name>Spring Modulith - Examples - Kafka Example</name>
+	<artifactId>spring-modulith-example-kafka</artifactId>
+
+	<dependencies>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.modulith</groupId>
+			<artifactId>spring-modulith-starter-jpa</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.modulith</groupId>
+			<artifactId>spring-modulith-events-kafka</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.kafka</groupId>
+			<artifactId>spring-kafka</artifactId>
+		</dependency>
+
+		<!-- jMolecules -->
+
+		<dependency>
+			<groupId>org.jmolecules.integrations</groupId>
+			<artifactId>jmolecules-starter-ddd</artifactId>
+		</dependency>
+
+	</dependencies>
+
+</project>