diff --git a/src/main/java/guru/springframework/sfgdi/controllers/ConstructorInjectedController.java b/src/main/java/guru/springframework/sfgdi/controllers/ConstructorInjectedController.java
index 42afc32977..a09934a4ba 100644
--- a/src/main/java/guru/springframework/sfgdi/controllers/ConstructorInjectedController.java
+++ b/src/main/java/guru/springframework/sfgdi/controllers/ConstructorInjectedController.java
@@ -1,6 +1,7 @@
 package guru.springframework.sfgdi.controllers;
 
 import guru.springframework.sfgdi.services.GreetingService;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Controller;
 
 @Controller
@@ -8,7 +9,7 @@ public class ConstructorInjectedController {
 
     private final GreetingService greetingService;
 
-    public ConstructorInjectedController(GreetingService greetingService) {
+    public ConstructorInjectedController(@Qualifier("constructorGreetingService") GreetingService greetingService) {
         this.greetingService = greetingService;
     }
 
diff --git a/src/main/java/guru/springframework/sfgdi/controllers/PropertyInjectedController.java b/src/main/java/guru/springframework/sfgdi/controllers/PropertyInjectedController.java
index f3ee00fb04..cc95f1d896 100644
--- a/src/main/java/guru/springframework/sfgdi/controllers/PropertyInjectedController.java
+++ b/src/main/java/guru/springframework/sfgdi/controllers/PropertyInjectedController.java
@@ -2,12 +2,14 @@
 
 import guru.springframework.sfgdi.services.GreetingService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Controller;
 
 @Controller
 public class PropertyInjectedController {
 
     @Autowired
+    @Qualifier("propertyInjectedGreetingService")
     public GreetingService greetingService;
 
     public String getGretting() {
diff --git a/src/main/java/guru/springframework/sfgdi/controllers/SetterInjectedController.java b/src/main/java/guru/springframework/sfgdi/controllers/SetterInjectedController.java
index 99a609fa10..74c2b7a150 100644
--- a/src/main/java/guru/springframework/sfgdi/controllers/SetterInjectedController.java
+++ b/src/main/java/guru/springframework/sfgdi/controllers/SetterInjectedController.java
@@ -2,6 +2,7 @@
 
 import guru.springframework.sfgdi.services.GreetingService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Controller;
 
 @Controller
@@ -11,6 +12,7 @@ public class SetterInjectedController {
     private GreetingService greetingService;
 
     @Autowired
+    @Qualifier("setterInjectedGreetingService")
     public void setGreetingService(GreetingService greetingService) {
         this.greetingService = greetingService;
     }
diff --git a/src/main/java/guru/springframework/sfgdi/services/ConstructorGreetingService.java b/src/main/java/guru/springframework/sfgdi/services/ConstructorGreetingService.java
new file mode 100644
index 0000000000..ef6ca5dfaa
--- /dev/null
+++ b/src/main/java/guru/springframework/sfgdi/services/ConstructorGreetingService.java
@@ -0,0 +1,11 @@
+package guru.springframework.sfgdi.services;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class ConstructorGreetingService implements GreetingService {
+    @Override
+    public String sayGreeting() {
+        return "Hello World! - Constructor";
+    }
+}
diff --git a/src/main/java/guru/springframework/sfgdi/services/PropertyInjectedGreetingService.java b/src/main/java/guru/springframework/sfgdi/services/PropertyInjectedGreetingService.java
new file mode 100644
index 0000000000..f3f6773ce6
--- /dev/null
+++ b/src/main/java/guru/springframework/sfgdi/services/PropertyInjectedGreetingService.java
@@ -0,0 +1,11 @@
+package guru.springframework.sfgdi.services;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class PropertyInjectedGreetingService implements GreetingService {
+    @Override
+    public String sayGreeting() {
+        return "Hello World! - Property";
+    }
+}
diff --git a/src/main/java/guru/springframework/sfgdi/services/GreetingServiceImpl.java b/src/main/java/guru/springframework/sfgdi/services/SetterInjectedGreetingService.java
similarity index 58%
rename from src/main/java/guru/springframework/sfgdi/services/GreetingServiceImpl.java
rename to src/main/java/guru/springframework/sfgdi/services/SetterInjectedGreetingService.java
index 3eab8be6d5..36e76dd902 100644
--- a/src/main/java/guru/springframework/sfgdi/services/GreetingServiceImpl.java
+++ b/src/main/java/guru/springframework/sfgdi/services/SetterInjectedGreetingService.java
@@ -3,9 +3,9 @@
 import org.springframework.stereotype.Service;
 
 @Service
-public class GreetingServiceImpl implements GreetingService {
+public class SetterInjectedGreetingService implements GreetingService {
     @Override
     public String sayGreeting() {
-        return "Hello World!";
+        return "Hello World! - Setter";
     }
 }
diff --git a/src/test/java/guru/springframework/sfgdi/controllers/ConstructorInjectedControllerTest.java b/src/test/java/guru/springframework/sfgdi/controllers/ConstructorInjectedControllerTest.java
index 1123471b82..1878c78ae7 100644
--- a/src/test/java/guru/springframework/sfgdi/controllers/ConstructorInjectedControllerTest.java
+++ b/src/test/java/guru/springframework/sfgdi/controllers/ConstructorInjectedControllerTest.java
@@ -1,18 +1,16 @@
 package guru.springframework.sfgdi.controllers;
 
-import guru.springframework.sfgdi.services.GreetingServiceImpl;
+import guru.springframework.sfgdi.services.ConstructorGreetingService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
-
 class ConstructorInjectedControllerTest {
 
     ConstructorInjectedController controller;
 
     @BeforeEach
     void setUp() {
-        controller = new ConstructorInjectedController(new GreetingServiceImpl());
+        controller = new ConstructorInjectedController(new ConstructorGreetingService());
     }
 
     @Test
diff --git a/src/test/java/guru/springframework/sfgdi/controllers/PropertyInjectedControllerTest.java b/src/test/java/guru/springframework/sfgdi/controllers/PropertyInjectedControllerTest.java
index e5c8304b51..c4d8591744 100644
--- a/src/test/java/guru/springframework/sfgdi/controllers/PropertyInjectedControllerTest.java
+++ b/src/test/java/guru/springframework/sfgdi/controllers/PropertyInjectedControllerTest.java
@@ -1,11 +1,9 @@
 package guru.springframework.sfgdi.controllers;
 
-import guru.springframework.sfgdi.services.GreetingServiceImpl;
+import guru.springframework.sfgdi.services.ConstructorGreetingService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
-
 class PropertyInjectedControllerTest {
 
     PropertyInjectedController controller;
@@ -14,7 +12,7 @@ class PropertyInjectedControllerTest {
     void setUp() {
         controller = new PropertyInjectedController();
 
-        controller.greetingService = new GreetingServiceImpl();
+        controller.greetingService = new ConstructorGreetingService();
     }
 
     @Test
diff --git a/src/test/java/guru/springframework/sfgdi/controllers/SetterInjectedControllerTest.java b/src/test/java/guru/springframework/sfgdi/controllers/SetterInjectedControllerTest.java
index 556cffad1f..0f6c0e8d7e 100644
--- a/src/test/java/guru/springframework/sfgdi/controllers/SetterInjectedControllerTest.java
+++ b/src/test/java/guru/springframework/sfgdi/controllers/SetterInjectedControllerTest.java
@@ -1,11 +1,9 @@
 package guru.springframework.sfgdi.controllers;
 
-import guru.springframework.sfgdi.services.GreetingServiceImpl;
+import guru.springframework.sfgdi.services.ConstructorGreetingService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
-
 class SetterInjectedControllerTest {
 
     SetterInjectedController controller;
@@ -13,7 +11,7 @@ class SetterInjectedControllerTest {
     @BeforeEach
     void setUp() {
         controller = new SetterInjectedController();
-        controller.setGreetingService(new GreetingServiceImpl());
+        controller.setGreetingService(new ConstructorGreetingService());
     }
 
     @Test