BAEL-3682 add sample of http message converter beans autoconfiguration

spring-boot-rest/src/main/java/com/baeldung/spring/ConverterExtensionsConfig.java

@@ -0,0 +1,30 @@
+package com.baeldung.spring;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.xml.MarshallingHttpMessageConverter;
+import org.springframework.oxm.xstream.XStreamMarshaller;
+
+/**
+ * Another possibility is to create a bean which will be automatically added to the Spring Boot Autoconfigurations.
+ *
+ * ATTENTION: Multiple converter registration of the same type most likely causes problem (serialize twice, etc.)
+ * Therefore, be sure to remove manually added XML message converter first then uncomment
+ * this @{@link org.springframework.context.annotation.Configuration} to use
+ */
+//@Configuration
+public class ConverterExtensionsConfig {
+
+    @Bean
+    public HttpMessageConverter<Object> createXmlHttpMessageConverter() {
+        final MarshallingHttpMessageConverter xmlConverter = new MarshallingHttpMessageConverter();
+
+        final XStreamMarshaller xstreamMarshaller = new XStreamMarshaller();
+        xstreamMarshaller.setAutodetectAnnotations(true);
+        xmlConverter.setMarshaller(xstreamMarshaller);
+        xmlConverter.setUnmarshaller(xstreamMarshaller);
+
+        return xmlConverter;
+    }
+
+}