diff --git a/docker-example-service/pom.xml b/docker-example-service/pom.xml
index 428baa8..c5dc14b 100644
--- a/docker-example-service/pom.xml
+++ b/docker-example-service/pom.xml
@@ -7,7 +7,6 @@
     </parent>
 
     <modelVersion>4.0.0</modelVersion>
-    <groupId>com.basaki.example</groupId>
     <artifactId>docker-example-service</artifactId>
     <packaging>jar</packaging>
     <version>1.0</version>
diff --git a/docker-example-service/src/main/java/com/basaki/example/docker/controller/BookController.java b/docker-example-service/src/main/java/com/basaki/example/docker/controller/BookController.java
index b418a87..731a226 100644
--- a/docker-example-service/src/main/java/com/basaki/example/docker/controller/BookController.java
+++ b/docker-example-service/src/main/java/com/basaki/example/docker/controller/BookController.java
@@ -8,16 +8,19 @@
 import io.swagger.annotations.ApiOperation;
 import io.swagger.annotations.ApiResponse;
 import io.swagger.annotations.ApiResponses;
+
 import java.util.List;
 import java.util.UUID;
+
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
@@ -34,7 +37,6 @@
 @RestController
 @Slf4j
 @Api(value = "Book API",
-        description = "Book API",
         produces = "application/json", tags = {"API"})
 public class BookController {
 
@@ -52,7 +54,7 @@ public class BookController {
     @ApiResponses({
             @ApiResponse(code = 201, response = Override.class,
                     message = "Override override created successfully")})
-    @RequestMapping(method = RequestMethod.POST, value = BOOK_URL,
+    @PostMapping(value = BOOK_URL,
             consumes = MediaType.APPLICATION_JSON_VALUE,
             produces = MediaType.APPLICATION_JSON_VALUE)
     @ResponseStatus(HttpStatus.CREATED)
@@ -64,7 +66,7 @@ public Book create(@RequestBody BookRequest request) {
             value = "Retrieves a book by ID.",
             notes = "Requires a book identifier",
             response = Book.class)
-    @RequestMapping(method = RequestMethod.GET, value = BOOK_BY_ID_URL,
+    @GetMapping(value = BOOK_BY_ID_URL,
             produces = {MediaType.APPLICATION_JSON_VALUE})
     @ResponseBody
     public Book getById(@PathVariable("id") UUID id) {
@@ -75,7 +77,7 @@ public Book getById(@PathVariable("id") UUID id) {
             value = "Retrieves all books associated with a title, genre, publisher or combination of them.",
             notes = "In absence of any parameter, it will return all authors",
             response = Book.class, responseContainer = "List")
-    @RequestMapping(method = RequestMethod.GET, value = BOOK_URL,
+    @GetMapping(value = BOOK_URL,
             produces = {MediaType.APPLICATION_JSON_VALUE})
     @ResponseBody
     public List<Book> get(
@@ -86,14 +88,14 @@ public List<Book> get(
     }
 
     @ApiOperation(value = "Deletes a book by ID.")
-    @RequestMapping(method = RequestMethod.DELETE, value = BOOK_BY_ID_URL)
+    @DeleteMapping(value = BOOK_BY_ID_URL)
     @ResponseBody
     public void deleteById(@PathVariable("id") UUID id) {
         service.delete(id);
     }
 
     @ApiOperation(value = "Deletes all books.")
-    @RequestMapping(method = RequestMethod.DELETE, value = BOOK_URL)
+    @DeleteMapping(value = BOOK_URL)
     @ResponseBody
     public void deleteAll() {
         service.deleteAll();
diff --git a/docker-example-service/src/main/java/com/basaki/example/docker/controller/LandingController.java b/docker-example-service/src/main/java/com/basaki/example/docker/controller/LandingController.java
index 8290e23..4f64e10 100644
--- a/docker-example-service/src/main/java/com/basaki/example/docker/controller/LandingController.java
+++ b/docker-example-service/src/main/java/com/basaki/example/docker/controller/LandingController.java
@@ -2,7 +2,8 @@
 
 import java.io.IOException;
 import javax.servlet.http.HttpServletResponse;
-import org.springframework.web.bind.annotation.RequestMapping;
+
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 import springfox.documentation.annotations.ApiIgnore;
 
@@ -17,7 +18,7 @@
 @ApiIgnore
 public class LandingController {
 
-    @RequestMapping("/")
+    @GetMapping("/")
     public void home(HttpServletResponse response) throws IOException {
         response.sendRedirect("/swagger-ui.html");
     }
diff --git a/docker-example-service/src/main/java/com/basaki/example/docker/service/BookService.java b/docker-example-service/src/main/java/com/basaki/example/docker/service/BookService.java
index e50ee15..4e3970c 100644
--- a/docker-example-service/src/main/java/com/basaki/example/docker/service/BookService.java
+++ b/docker-example-service/src/main/java/com/basaki/example/docker/service/BookService.java
@@ -4,6 +4,8 @@
 import com.basaki.example.docker.model.Book;
 import com.basaki.example.docker.model.BookRequest;
 import com.basaki.example.docker.model.Genre;
+
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -64,34 +66,18 @@ public Book getById(UUID id) {
     public List<Book> get(String title, Genre genre, String publisher) {
 
         if (title == null && genre == null && publisher == null) {
-            return bookMap.values().stream().collect(Collectors.toList());
+            return new ArrayList<>(bookMap.values());
         }
 
-        List<Book> books = bookMap.values().stream().filter(b -> {
-            if (title != null && title.equalsIgnoreCase(b.getTitle())) {
-                return true;
-            } else {
-                return true;
-            }
-        }).filter(b -> {
-            if (genre != null && genre.equals(b.getGenre())) {
-                return true;
-            } else {
-                return true;
-            }
-        }).filter(b -> {
-            if (publisher != null && publisher.equalsIgnoreCase(
-                    b.getPublisher())) {
-                return true;
-            } else {
-                return true;
-            }
-        }).collect(Collectors.toList());
-
-        if (books == null || books.size() == 0) {
+        List<Book> books = bookMap.values().stream()
+                .filter(b -> title != null && title.equalsIgnoreCase(b.getTitle()))
+                .filter(b -> genre != null && genre.equals(b.getGenre()))
+                .filter(b -> publisher != null && publisher.equalsIgnoreCase(b.getPublisher()))
+                .collect(Collectors.toList());
+
+        if (books.isEmpty()) {
             throw new InvalidSearchException("No books found!");
         }
-
         return books;
     }
 
diff --git a/docker-example-service/src/main/java/com/basaki/example/docker/util/UuidBeanFactory.java b/docker-example-service/src/main/java/com/basaki/example/docker/util/UuidBeanFactory.java
index 6d440d9..316548b 100644
--- a/docker-example-service/src/main/java/com/basaki/example/docker/util/UuidBeanFactory.java
+++ b/docker-example-service/src/main/java/com/basaki/example/docker/util/UuidBeanFactory.java
@@ -19,8 +19,7 @@ public Object createBean(Object source, Class<?> sourceClass,
         }
 
         UUID uuidSrc = (UUID) source;
-        UUID uuidDest = new UUID(uuidSrc.getMostSignificantBits(),
+        return new UUID(uuidSrc.getMostSignificantBits(),
                 uuidSrc.getLeastSignificantBits());
-        return uuidDest;
     }
 }