diff --git a/jackson/src/test/java/org/baeldung/jackson/dtos/MyDto.java b/jackson/src/test/java/org/baeldung/jackson/dtos/MyDto.java
index d9bfe6f8f6..668eea3fcc 100644
--- a/jackson/src/test/java/org/baeldung/jackson/dtos/MyDto.java
+++ b/jackson/src/test/java/org/baeldung/jackson/dtos/MyDto.java
@@ -44,4 +44,11 @@ public class MyDto {
         this.booleanValue = booleanValue;
     }
 
+    //
+
+    @Override
+    public String toString() {
+        return "MyDto [stringValue=" + stringValue + ", intValue=" + intValue + ", booleanValue=" + booleanValue + "]";
+    }
+
 }
diff --git a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoAccessLevel.java b/jackson/src/test/java/org/baeldung/jackson/field/MyDtoAccessLevel.java
index d1761b30ed..c164b00e4a 100644
--- a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoAccessLevel.java
+++ b/jackson/src/test/java/org/baeldung/jackson/field/MyDtoAccessLevel.java
@@ -4,17 +4,19 @@ public class MyDtoAccessLevel {
 
     private String stringValue;
     int intValue;
+    protected float floatValue;
     public boolean booleanValue;
 
     public MyDtoAccessLevel() {
         super();
     }
 
-    public MyDtoAccessLevel(final String stringValue, final int intValue, final boolean booleanValue) {
+    public MyDtoAccessLevel(final String stringValue, final int intValue, final float floatValue, final boolean booleanValue) {
         super();
 
         this.stringValue = stringValue;
         this.intValue = intValue;
+        this.floatValue = floatValue;
         this.booleanValue = booleanValue;
     }
 
diff --git a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetterImplicitDeserialization.java b/jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetterImplicitDeserialization.java
deleted file mode 100644
index 0c5027ac24..0000000000
--- a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetterImplicitDeserialization.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package org.baeldung.jackson.field;
-
-public class MyDtoGetterImplicitDeserialization {
-
-    private String stringValue;
-
-    public MyDtoGetterImplicitDeserialization() {
-        super();
-    }
-
-    public MyDtoGetterImplicitDeserialization(final String stringValue) {
-        super();
-
-        this.stringValue = stringValue;
-    }
-
-    // API
-
-    public String getStringValue() {
-        return stringValue;
-    }
-
-}
diff --git a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetter.java b/jackson/src/test/java/org/baeldung/jackson/field/MyDtoWithGetter.java
similarity index 69%
rename from jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetter.java
rename to jackson/src/test/java/org/baeldung/jackson/field/MyDtoWithGetter.java
index b0725b9d65..0f15b2fcc3 100644
--- a/jackson/src/test/java/org/baeldung/jackson/field/MyDtoGetter.java
+++ b/jackson/src/test/java/org/baeldung/jackson/field/MyDtoWithGetter.java
@@ -1,15 +1,15 @@
 package org.baeldung.jackson.field;
 
-public class MyDtoGetter {
+public class MyDtoWithGetter {
 
     private String stringValue;
     private int intValue;
 
-    public MyDtoGetter() {
+    public MyDtoWithGetter() {
         super();
     }
 
-    public MyDtoGetter(final String stringValue, final int intValue) {
+    public MyDtoWithGetter(final String stringValue, final int intValue) {
         super();
 
         this.stringValue = stringValue;
diff --git a/jackson/src/test/java/org/baeldung/jackson/test/JacksonFieldUnitTest.java b/jackson/src/test/java/org/baeldung/jackson/test/JacksonFieldUnitTest.java
index 44c2ba534d..8e67144d43 100644
--- a/jackson/src/test/java/org/baeldung/jackson/test/JacksonFieldUnitTest.java
+++ b/jackson/src/test/java/org/baeldung/jackson/test/JacksonFieldUnitTest.java
@@ -9,9 +9,8 @@ import static org.junit.Assert.assertThat;
 import java.io.IOException;
 
 import org.baeldung.jackson.field.MyDtoAccessLevel;
-import org.baeldung.jackson.field.MyDtoGetter;
-import org.baeldung.jackson.field.MyDtoGetterImplicitDeserialization;
 import org.baeldung.jackson.field.MyDtoSetter;
+import org.baeldung.jackson.field.MyDtoWithGetter;
 import org.junit.Test;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
@@ -30,6 +29,7 @@ public class JacksonFieldUnitTest {
         final String dtoAsString = mapper.writeValueAsString(dtoObject);
         assertThat(dtoAsString, not(containsString("stringValue")));
         assertThat(dtoAsString, not(containsString("intValue")));
+        assertThat(dtoAsString, not(containsString("floatValue")));
         assertThat(dtoAsString, containsString("booleanValue"));
         System.out.println(dtoAsString);
     }
@@ -38,7 +38,7 @@ public class JacksonFieldUnitTest {
     public final void givenDifferentAccessLevels_whenGetterAdded_thenSerializable() throws JsonProcessingException {
         final ObjectMapper mapper = new ObjectMapper();
 
-        final MyDtoGetter dtoObject = new MyDtoGetter();
+        final MyDtoWithGetter dtoObject = new MyDtoWithGetter();
 
         final String dtoAsString = mapper.writeValueAsString(dtoObject);
         assertThat(dtoAsString, containsString("stringValue"));
@@ -51,7 +51,7 @@ public class JacksonFieldUnitTest {
         final String jsonAsString = "{\"stringValue\":\"dtoString\"}";
         final ObjectMapper mapper = new ObjectMapper();
 
-        final MyDtoGetterImplicitDeserialization dtoObject = mapper.readValue(jsonAsString, MyDtoGetterImplicitDeserialization.class);
+        final MyDtoWithGetter dtoObject = mapper.readValue(jsonAsString, MyDtoWithGetter.class);
 
         assertNotNull(dtoObject);
         assertThat(dtoObject.getStringValue(), equalTo("dtoString"));
diff --git a/jackson/src/test/java/org/baeldung/jackson/test/JacksonSerializationIgnoreUnitTest.java b/jackson/src/test/java/org/baeldung/jackson/test/JacksonSerializationIgnoreUnitTest.java
index d0e0426ff0..64614fb854 100644
--- a/jackson/src/test/java/org/baeldung/jackson/test/JacksonSerializationIgnoreUnitTest.java
+++ b/jackson/src/test/java/org/baeldung/jackson/test/JacksonSerializationIgnoreUnitTest.java
@@ -225,21 +225,25 @@ public class JacksonSerializationIgnoreUnitTest {
     }
 
     @Test
-    public final void givenAllowingMapObjectWithNullKey_whenWritingMapObjectWithNullKey_thenAllowed() throws JsonProcessingException {
+    public final void givenAllowingMapObjectWithNullKey_whenWriting_thenCorrect() throws JsonProcessingException {
         final ObjectMapper mapper = new ObjectMapper();
         mapper.getSerializerProvider().setNullKeySerializer(new MyDtoNullKeySerializer());
 
-        final MyDto dtoObject = new MyDto();
-        dtoObject.setStringValue("dtoObjectString");
+        final MyDto dtoObject1 = new MyDto();
+        dtoObject1.setStringValue("dtoObjectString1");
+        final MyDto dtoObject2 = new MyDto();
+        dtoObject2.setStringValue("dtoObjectString2");
 
         final Map<String, MyDto> dtoMap = new HashMap<String, MyDto>();
-        dtoMap.put(null, dtoObject);
+        dtoMap.put(null, dtoObject1);
+        dtoMap.put("obj2", dtoObject2);
 
         final String dtoMapAsString = mapper.writeValueAsString(dtoMap);
 
-        assertThat(dtoMapAsString, containsString(""));
-        assertThat(dtoMapAsString, containsString("dtoObjectString"));
         System.out.println(dtoMapAsString);
+        assertThat(dtoMapAsString, containsString("\"\""));
+        assertThat(dtoMapAsString, containsString("dtoObjectString1"));
+        assertThat(dtoMapAsString, containsString("obj2"));
     }
 
     @Test