HttpMediaTypeNotAcceptableException (#2145)

* code snippets for the `Java 9 Stream API improvements` article

* code snippets for the `Java 9 Stream API improvements` article [2 attempt]

* removed the first attempt

* the Spring 5 WebClient

* delted stream features test

* HttpMediaTypeNotAcceptableExceptionExampleController [0]

* reactive web client service was removed

spring-mvc-java/src/main/java/com/baeldung/exception/HttpMediaTypeNotAcceptableExceptionExampleController.java

@@ -0,0 +1,27 @@
+package com.baeldung.exception;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.HttpMediaTypeNotAcceptableException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Collections;
+import java.util.Map;
+
+@RestController
+public class HttpMediaTypeNotAcceptableExceptionExampleController {
+
+    @PostMapping(value = "/test", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
+    public Map<String, String> test() {
+        return Collections.singletonMap("key", "value");
+    }
+
+    @ResponseBody
+    @ExceptionHandler(HttpMediaTypeNotAcceptableException.class)
+    public String handleHttpMediaTypeNotAcceptableException() {
+        return "acceptable MIME type:" + MediaType.APPLICATION_JSON_VALUE;
+    }
+
+}