BAEL-1649 Difference between @Controller and @RestController (#3885)

* Difference between @Controller and @RestController

* Difference between @Controller and @RestController - test fix

spring-mvc-java/src/main/java/com/baeldung/model/Book.java

@@ -0,0 +1,33 @@
+package com.baeldung.model;
+
+public class Book {
+
+    private int id;
+    private String author;
+    private String title;
+
+    public int getId() {
+        return id;
+    }
+    
+    public void setId(int id) {
+        this.id = id;
+    }
+    
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+    
+}