From c60e01034dd97b65c7908c5aec8baec2bbf4ce75 Mon Sep 17 00:00:00 2001
From: mikr <michael.krimgen@ximedes.com>
Date: Sun, 28 Feb 2021 22:50:54 +0100
Subject: [PATCH] JAVA-4215 Fix issue in "Jackson Bidirectional Rels" article

---
 .../jackson/bidirection/ItemWithRef.java      |  4 +-
 .../jackson/bidirection/UserWithRef.java      |  6 +--
 .../JacksonBidirectionRelationUnitTest.java   | 37 ++++++++++++++++---
 3 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/ItemWithRef.java b/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/ItemWithRef.java
index 0ca8d721e8..1bd2451c6c 100644
--- a/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/ItemWithRef.java
+++ b/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/ItemWithRef.java
@@ -1,12 +1,12 @@
 package com.baeldung.jackson.bidirection;
 
-import com.fasterxml.jackson.annotation.JsonManagedReference;
+import com.fasterxml.jackson.annotation.JsonBackReference;
 
 public class ItemWithRef {
     public int id;
     public String itemName;
 
-    @JsonManagedReference
+    @JsonBackReference
     public UserWithRef owner;
 
     public ItemWithRef() {
diff --git a/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/UserWithRef.java b/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/UserWithRef.java
index 3de03fc651..cc7b2b52ca 100644
--- a/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/UserWithRef.java
+++ b/jackson-modules/jackson-annotations/src/main/java/com/baeldung/jackson/bidirection/UserWithRef.java
@@ -3,13 +3,13 @@ package com.baeldung.jackson.bidirection;
 import java.util.ArrayList;
 import java.util.List;
 
-import com.fasterxml.jackson.annotation.JsonBackReference;
+import com.fasterxml.jackson.annotation.JsonManagedReference;
 
 public class UserWithRef {
     public int id;
     public String name;
 
-    @JsonBackReference
+    @JsonManagedReference
     public List<ItemWithRef> userItems;
 
     public UserWithRef() {
@@ -19,7 +19,7 @@ public class UserWithRef {
     public UserWithRef(final int id, final String name) {
         this.id = id;
         this.name = name;
-        userItems = new ArrayList<ItemWithRef>();
+        userItems = new ArrayList<>();
     }
 
     public void addItem(final ItemWithRef item) {
diff --git a/jackson-modules/jackson-annotations/src/test/java/com/baeldung/jackson/bidirection/JacksonBidirectionRelationUnitTest.java b/jackson-modules/jackson-annotations/src/test/java/com/baeldung/jackson/bidirection/JacksonBidirectionRelationUnitTest.java
index d0c5209891..b3ce27ad94 100644
--- a/jackson-modules/jackson-annotations/src/test/java/com/baeldung/jackson/bidirection/JacksonBidirectionRelationUnitTest.java
+++ b/jackson-modules/jackson-annotations/src/test/java/com/baeldung/jackson/bidirection/JacksonBidirectionRelationUnitTest.java
@@ -1,7 +1,9 @@
 package com.baeldung.jackson.bidirection;
 
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 
@@ -16,7 +18,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 
 public class JacksonBidirectionRelationUnitTest {
 
-    @Test(expected = JsonMappingException.class)
+    @Test (expected = JsonMappingException.class)
     public void givenBidirectionRelation_whenSerializing_thenException() throws JsonProcessingException {
         final User user = new User(1, "John");
         final Item item = new Item(2, "book", user);
@@ -26,16 +28,39 @@ public class JacksonBidirectionRelationUnitTest {
     }
 
     @Test
-    public void givenBidirectionRelation_whenUsingJacksonReferenceAnnotation_thenCorrect() throws JsonProcessingException {
+    public void givenBidirectionRelation_whenUsingJacksonReferenceAnnotationWithSerialization_thenCorrect() throws JsonProcessingException {
         final UserWithRef user = new UserWithRef(1, "John");
         final ItemWithRef item = new ItemWithRef(2, "book", user);
         user.addItem(item);
 
-        final String result = new ObjectMapper().writeValueAsString(item);
+        final String itemJson = new ObjectMapper().writeValueAsString(item);
+        final String userJson = new ObjectMapper().writeValueAsString(user);
 
-        assertThat(result, containsString("book"));
-        assertThat(result, containsString("John"));
-        assertThat(result, not(containsString("userItems")));
+        assertThat(itemJson, containsString("book"));
+        assertThat(itemJson, not(containsString("John")));
+
+        assertThat(userJson, containsString("John"));
+        assertThat(userJson, containsString("userItems"));
+        assertThat(userJson, containsString("book"));
+    }
+
+    @Test
+    public void givenBidirectionRelation_whenUsingJacksonReferenceAnnotationWithDeserialization_thenCorrect() throws JsonProcessingException {
+        final UserWithRef user = new UserWithRef(1, "John");
+        final ItemWithRef item = new ItemWithRef(2, "book", user);
+        user.addItem(item);
+
+        final String itemJson = new ObjectMapper().writeValueAsString(item);
+        final String userJson = new ObjectMapper().writeValueAsString(user);
+
+        final ItemWithRef itemRead = new ObjectMapper().readValue(itemJson, ItemWithRef.class);
+        final UserWithRef userRead = new ObjectMapper().readValue(userJson, UserWithRef.class);
+
+        assertThat(itemRead.itemName, is("book"));
+        assertThat(itemRead.owner, nullValue());
+
+        assertThat(userRead.name, is("John"));
+        assertThat(userRead.userItems.get(0).itemName, is("book"));
     }
 
     @Test