done

.gitignore

@@ -1,3 +1,5 @@
 .idea/*
 *.iml
 target/*
+*.log
+

pom.xml

@@ -24,6 +24,17 @@
             <version>4.12</version>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-api</artifactId>
+            <version>2.23.1</version> <!-- 'x' should be changed to the most recent version number. -->
+        </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-core</artifactId>
+            <version>2.23.1</version> <!-- 'x' should be changed to the most recent version number. -->
+        </dependency>
     </dependencies>
     <build>
         <plugins>

src/main/java/mate/academy/service/AuthenticationServiceImpl.java

@@ -2,11 +2,16 @@
 
 import mate.academy.exception.AuthenticationException;
 import mate.academy.model.User;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 public class AuthenticationServiceImpl implements AuthenticationService {
+
+    private Logger logger = LogManager.getLogger(AuthenticationServiceImpl.class);
+
     @Override
     public User login(String login, String password) throws AuthenticationException {
-        //TODO: add corresponding log message about method login was called
+        logger.info("Method login was called. Params: login={}", login);
         User user = findByLogin(login);
         if (!user.getPassword().equals(password)) {
             throw new AuthenticationException("Username or password are incorrect");
@@ -20,4 +25,12 @@ private User findByLogin(String login) {
         user.setUserId(2L);
         return user;
     }
+
+    public void setLogger(Logger logger) {
+        this.logger = logger;
+    }
+
+    public Logger getLogger() {
+        return logger;
+    }
 }

src/main/java/mate/academy/service/OrderServiceImpl.java

@@ -4,27 +4,36 @@
 import java.util.List;
 import mate.academy.model.Order;
 import mate.academy.model.Product;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 public class OrderServiceImpl implements OrderService {
+
+    private Logger logger = LogManager.getLogger(OrderServiceImpl.class);
+
     @Override
     public Order completeOrder(Long userId) {
-        // TODO: add log message about method completeOrder was called
+        logger.info("Method completeOrder was called with userId: {}", userId);
         List<Product> products = getAllProductsFromShoppingCart(userId);
         Order order = new Order(products, userId);
-        // NOTE: In production ready code this order identifier should be generated by DB
-        // For test purpose we simplify this and return dummy data
         order.setOrderId(1L);
         return order;
     }
 
     private List<Product> getAllProductsFromShoppingCart(Long userId) {
-        // NOTE: In production ready code this method should fetch data from DB
-        // For test purpose we simplify this method and return dummy data
         Product iphone = new Product("iPhone X", BigDecimal.valueOf(1199));
         Product macBook = new Product("MacBook Air 2020", BigDecimal.valueOf(1399));
         Product xiaomi = new Product("Xiaomi 12", BigDecimal.valueOf(499));
         List<Product> products = List.of(iphone, macBook, xiaomi);
-        // TODO: add log message about successful fetched data from DB
+        logger.info("Successfully fetched data from DB for userId: {}", userId);
         return products;
     }
+
+    public void setLogger(Logger logger) {
+        this.logger = logger;
+    }
+
+    public Logger getLogger() {
+        return logger;
+    }
 }

src/main/resources/ log4j2.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="INFO">
+    <!-- Define the appenders -->
+    <Appenders>
+        <!-- Console Appender -->
+        <Console name="ConsoleAppender" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss} [%t] %-5level %logger{36} - %msg%n" />
+        </Console>
+        <!-- File Appender -->
+        <File name="FileAppender" fileName="applogs/application_logs.log">
+            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss} [%t] %-5level %logger{36} - %msg%n" />
+        </File>
+    </Appenders>
+    <!-- Define the loggers -->
+    <Loggers>
+        <!-- Root Logger -->
+        <Root level="info">
+            <AppenderRef ref="ConsoleAppender" />
+            <AppenderRef ref="FileAppender" />
+        </Root>
+        <!-- Logger for specific package -->
+        <Logger name="com.example.myapp" level="debug">
+            <AppenderRef ref="FileAppender" />
+        </Logger>
+    </Loggers>
+</Configuration>