diff --git a/core-java/service-provider-interface/standard-library/pom.xml b/core-java/service-provider-interface/classics-library/pom.xml
similarity index 92%
rename from core-java/service-provider-interface/standard-library/pom.xml
rename to core-java/service-provider-interface/classics-library/pom.xml
index 143b32a..55fcd31 100644
--- a/core-java/service-provider-interface/standard-library/pom.xml
+++ b/core-java/service-provider-interface/classics-library/pom.xml
@@ -9,9 +9,9 @@
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
-    <artifactId>standard-library</artifactId>
+    <artifactId>classics-library</artifactId>
 
-    <name>standard-library</name>
+    <name>classics-library</name>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
diff --git a/core-java/service-provider-interface/standard-library/src/main/java/org/library/StandardLibrary.java b/core-java/service-provider-interface/classics-library/src/main/java/org/library/ClassicsLibrary.java
similarity index 66%
rename from core-java/service-provider-interface/standard-library/src/main/java/org/library/StandardLibrary.java
rename to core-java/service-provider-interface/classics-library/src/main/java/org/library/ClassicsLibrary.java
index 5d2b0e7..feb110e 100644
--- a/core-java/service-provider-interface/standard-library/src/main/java/org/library/StandardLibrary.java
+++ b/core-java/service-provider-interface/classics-library/src/main/java/org/library/ClassicsLibrary.java
@@ -6,20 +6,29 @@ import java.util.TreeMap;
 import org.library.spi.Book;
 import org.library.spi.Library;
 
-public class StandardLibrary implements Library {
+public class ClassicsLibrary implements Library {
 
+    public static final String CLASSICS_LIBRARY = "CLASSICS";
     private final Map<String, Book> books;
 
-    public StandardLibrary() {
+    public ClassicsLibrary() {
         books = new TreeMap<>();
         Book nineteenEightyFour = new Book("Nineteen Eighty-Four", "George Orwell",
                 "It was a bright cold day in April, and the clocks were striking thirteen.");
         Book theLordOfTheRings = new Book("The Lord of the Rings", "J. R. R. Tolkien",
                 "When Mr. Bilbo Baggins of Bag End announced that he would shortly be celebrating his " +
                         "eleventy-first birthday with a party of special magnificence, there was much talk and excitement in Hobbiton.");
+        Book cleanCode = new Book("Clean Code", "Robert C. Martin",
+                "ClassicsEven bad code can function. But if code isn’t clean, it can bring a development organization to its knees");
 
         books.put("Nineteen Eighty-Four", nineteenEightyFour);
         books.put("The Lord of the Rings", theLordOfTheRings);
+        books.put("Clean Code", cleanCode);
+    }
+
+    @Override
+    public String getCategory() {
+        return CLASSICS_LIBRARY;
     }
 
     @Override
diff --git a/core-java/service-provider-interface/classics-library/src/main/resources/META-INF/services/org.library.spi.Library b/core-java/service-provider-interface/classics-library/src/main/resources/META-INF/services/org.library.spi.Library
new file mode 100644
index 0000000..08823fa
--- /dev/null
+++ b/core-java/service-provider-interface/classics-library/src/main/resources/META-INF/services/org.library.spi.Library
@@ -0,0 +1 @@
+org.library.ClassicsLibrary
diff --git a/core-java/service-provider-interface/custom-library/pom.xml b/core-java/service-provider-interface/computer-science-library/pom.xml
similarity index 89%
rename from core-java/service-provider-interface/custom-library/pom.xml
rename to core-java/service-provider-interface/computer-science-library/pom.xml
index aa007bf..14808e2 100644
--- a/core-java/service-provider-interface/custom-library/pom.xml
+++ b/core-java/service-provider-interface/computer-science-library/pom.xml
@@ -5,10 +5,10 @@
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>org.library</groupId>
-  <artifactId>custom-library</artifactId>
+  <artifactId>computer-science-library</artifactId>
   <version>1.0-SNAPSHOT</version>
 
-  <name>custom-library</name>
+  <name>computer-science-library</name>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
diff --git a/core-java/service-provider-interface/custom-library/src/main/java/org/library/CustomLibrary.java b/core-java/service-provider-interface/computer-science-library/src/main/java/org/library/ComputerScienceLibrary.java
similarity index 76%
rename from core-java/service-provider-interface/custom-library/src/main/java/org/library/CustomLibrary.java
rename to core-java/service-provider-interface/computer-science-library/src/main/java/org/library/ComputerScienceLibrary.java
index cc9bd4b..dcf8b63 100644
--- a/core-java/service-provider-interface/custom-library/src/main/java/org/library/CustomLibrary.java
+++ b/core-java/service-provider-interface/computer-science-library/src/main/java/org/library/ComputerScienceLibrary.java
@@ -6,11 +6,13 @@ import java.util.TreeMap;
 import org.library.spi.Book;
 import org.library.spi.Library;
 
-public class CustomLibrary implements Library {
+public class ComputerScienceLibrary implements Library {
+
+    public static final String COMPUTER_SCIENCE_LIBRARY = "COMPUTER_SCIENCE";
 
     private final Map<String, Book> books;
 
-    public CustomLibrary() {
+    public ComputerScienceLibrary() {
         books = new TreeMap<>();
 
         Book cleanCode = new Book("Clean Code", "Robert C. Martin",
@@ -22,6 +24,11 @@ public class CustomLibrary implements Library {
         books.put(pragmaticProgrammer.getName(), pragmaticProgrammer);
     }
 
+    @Override
+    public String getCategory() {
+        return COMPUTER_SCIENCE_LIBRARY;
+    }
+
     @Override
     public Book getBook(String name) {
         return books.get(name);
diff --git a/core-java/service-provider-interface/computer-science-library/src/main/resources/META-INF/services/org.library.spi.Library b/core-java/service-provider-interface/computer-science-library/src/main/resources/META-INF/services/org.library.spi.Library
new file mode 100644
index 0000000..e24f5e5
--- /dev/null
+++ b/core-java/service-provider-interface/computer-science-library/src/main/resources/META-INF/services/org.library.spi.Library
@@ -0,0 +1 @@
+org.library.ComputerScienceLibrary
diff --git a/core-java/service-provider-interface/custom-library/src/main/resources/META-INF/services/org.library.spi.Library b/core-java/service-provider-interface/custom-library/src/main/resources/META-INF/services/org.library.spi.Library
deleted file mode 100644
index 37ee10f..0000000
--- a/core-java/service-provider-interface/custom-library/src/main/resources/META-INF/services/org.library.spi.Library
+++ /dev/null
@@ -1 +0,0 @@
-org.library.CustomLibrary
diff --git a/core-java/service-provider-interface/library-demo/pom.xml b/core-java/service-provider-interface/library-client/pom.xml
similarity index 50%
rename from core-java/service-provider-interface/library-demo/pom.xml
rename to core-java/service-provider-interface/library-client/pom.xml
index 8f100d6..2b18cc4 100644
--- a/core-java/service-provider-interface/library-demo/pom.xml
+++ b/core-java/service-provider-interface/library-client/pom.xml
@@ -9,28 +9,47 @@
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
-    <artifactId>library-demo</artifactId>
+    <artifactId>library-client</artifactId>
 
-    <name>library-demo</name>
+    <name>library-client</name>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>1.8</maven.compiler.source>
-        <maven.compiler.target>1.8</maven.compiler.target>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
     </properties>
 
     <dependencies>
 
+
         <dependency>
             <groupId>org.library</groupId>
-            <artifactId>standard-library</artifactId>
+            <artifactId>computer-science-library</artifactId>
             <version>1.0-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.library</groupId>
-            <artifactId>custom-library</artifactId>
+            <artifactId>classics-library</artifactId>
+            <version>1.0-SNAPSHOT</version>
+        </dependency>
+        <dependency>
+            <groupId>org.library</groupId>
+            <artifactId>library-service-provider</artifactId>
             <version>1.0-SNAPSHOT</version>
         </dependency>
     </dependencies>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>11</source>
+                    <target>11</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
 </project>
diff --git a/core-java/service-provider-interface/library-client/src/main/java/org/library/LibraryClient.java b/core-java/service-provider-interface/library-client/src/main/java/org/library/LibraryClient.java
new file mode 100644
index 0000000..8e009c3
--- /dev/null
+++ b/core-java/service-provider-interface/library-client/src/main/java/org/library/LibraryClient.java
@@ -0,0 +1,22 @@
+package org.library;
+
+public class LibraryClient {
+    public static void main(String[] args) {
+        LibraryService libraryService = LibraryService.getInstance();
+        requestBook("Clean Code", libraryService);
+        requestBook("The Lord of the Rings", libraryService);
+        requestBook("The Lord of the Rings", "COMPUTER_SCIENCE", libraryService);
+    }
+
+    private static void requestBook(String bookName, LibraryService library) {
+        library.getBook(bookName)
+                .ifPresentOrElse(book -> System.out.println("The book '" + bookName + "' was found, here are the details:" + book),
+                        () -> System.out.println("The library doesn't have the book '" + bookName + "' that you need."));
+    }
+
+    private static void requestBook(String bookName,String category, LibraryService library) {
+        library.getBook(bookName, category)
+                .ifPresentOrElse(book -> System.out.println("The book '" + bookName + "' was found in  " + category + ", here are the details:" + book),
+                        () -> System.out.println("The library " + category + " doesn't have the book '" + bookName + "' that you need."));
+    }
+}
diff --git a/core-java/service-provider-interface/library-demo/src/main/java/org/library/LibraryDemo.java b/core-java/service-provider-interface/library-demo/src/main/java/org/library/LibraryDemo.java
deleted file mode 100644
index 9f131cb..0000000
--- a/core-java/service-provider-interface/library-demo/src/main/java/org/library/LibraryDemo.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package org.library;
-
-import org.library.spi.Book;
-
-public class LibraryDemo {
-    public static void main(String[] args) {
-        LibraryService libraryService = LibraryService.getInstance();
-        manageBookRequest("Clean Code", libraryService);
-        manageBookRequest("The Lord of the Rings", libraryService);
-    }
-
-    private static void manageBookRequest(String bookName, LibraryService library) {
-        Book book = library.getBook(bookName);
-        if (book == null) {
-            System.out.println("The library doesn't have the book '" + bookName + "' that you need.");
-        } else {
-            System.out.println("The book '" + bookName + "'was found, here are the details:" + book);
-        }
-    }
-}
diff --git a/core-java/service-provider-interface/library-service-provider/pom.xml b/core-java/service-provider-interface/library-service-provider/pom.xml
index 228f73c..e021cdb 100644
--- a/core-java/service-provider-interface/library-service-provider/pom.xml
+++ b/core-java/service-provider-interface/library-service-provider/pom.xml
@@ -16,5 +16,15 @@
     <maven.compiler.target>1.8</maven.compiler.target>
   </properties>
   <build>
+      <plugins>
+          <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-compiler-plugin</artifactId>
+              <configuration>
+                  <source>9</source>
+                  <target>9</target>
+              </configuration>
+          </plugin>
+      </plugins>
   </build>
 </project>
diff --git a/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/LibraryService.java b/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/LibraryService.java
index eb1cd91..465ac26 100644
--- a/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/LibraryService.java
+++ b/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/LibraryService.java
@@ -1,6 +1,8 @@
 package org.library;
 
 import java.util.Iterator;
+import java.util.Objects;
+import java.util.Optional;
 import java.util.ServiceLoader;
 
 import org.library.spi.Book;
@@ -22,13 +24,26 @@ public class LibraryService {
         return libraryService;
     }
 
-    public Book getBook(String name) {
+    public void refresh() {
+        loader.reload();
+    }
+
+    public Optional<Book> getBook(String name) {
         Book book = null;
         Iterator<Library> libraries = loader.iterator();
         while (book == null && libraries.hasNext()) {
             Library library = libraries.next();
             book = library.getBook(name);
         }
-        return book;
+        return Optional.ofNullable(book);
+    }
+
+    public Optional<Book> getBook(String name, String category) {
+        return loader.stream()
+                .map(ServiceLoader.Provider::get)
+                .filter(library -> library.getCategory().equals(category))
+                .map(library -> library.getBook(name))
+                .filter(Objects::nonNull)
+                .findFirst();
     }
 }
diff --git a/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/spi/Library.java b/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/spi/Library.java
index 9bea86d..a3068ec 100644
--- a/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/spi/Library.java
+++ b/core-java/service-provider-interface/library-service-provider/src/main/java/org/library/spi/Library.java
@@ -1,5 +1,6 @@
 package org.library.spi;
 
 public interface Library {
+    String getCategory();
     Book getBook(String name);
 }
diff --git a/core-java/service-provider-interface/pom.xml b/core-java/service-provider-interface/pom.xml
index 8b85719..25c7ae3 100644
--- a/core-java/service-provider-interface/pom.xml
+++ b/core-java/service-provider-interface/pom.xml
@@ -9,10 +9,10 @@
   <packaging>pom</packaging>
   <version>1.0-SNAPSHOT</version>
   <modules>
-    <module>library-demo</module>
+    <module>library-client</module>
     <module>library-service-provider</module>
-    <module>standard-library</module>
-    <module>custom-library</module>
+    <module>classics-library</module>
+    <module>computer-science-library</module>
   </modules>
 
   <name>Library Service Provider Example</name>
diff --git a/core-java/service-provider-interface/standard-library/src/main/resources/META-INF/services/org.library.spi.Library b/core-java/service-provider-interface/standard-library/src/main/resources/META-INF/services/org.library.spi.Library
deleted file mode 100644
index 587f111..0000000
--- a/core-java/service-provider-interface/standard-library/src/main/resources/META-INF/services/org.library.spi.Library
+++ /dev/null
@@ -1 +0,0 @@
-org.library.StandardLibrary