jv-logger

.gitignore

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

pom.xml

@@ -18,6 +18,18 @@
     </properties>
 
     <dependencies>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.9</version>
+        </dependency>
+
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.4.11</version>
+        </dependency>
+
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>

src/main/java/mate/academy/Main.java

@@ -6,17 +6,28 @@
 import mate.academy.service.AuthenticationServiceImpl;
 import mate.academy.service.OrderService;
 import mate.academy.service.OrderServiceImpl;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class Main {
+    private static final Logger logger = LoggerFactory.getLogger(Main.class);
+
     public static void main(String[] args) {
+        logger.info("Application started");
+
         AuthenticationService authenticationService = new AuthenticationServiceImpl();
         User user;
+
+        String login = "bob";
+        String password = "1234";
+
         try {
-            user = authenticationService.login("bob", "1234");
+            user = authenticationService.login(login, password);
         } catch (AuthenticationException e) {
-            e.printStackTrace();
+            logger.error("Login failed for user. login={}", login, e);
             return;
         }
+
         OrderService orderService = new OrderServiceImpl();
         orderService.completeOrder(user.getUserId());
     }

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

@@ -2,21 +2,29 @@
 
 import mate.academy.exception.AuthenticationException;
 import mate.academy.model.User;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class AuthenticationServiceImpl implements AuthenticationService {
+    private static final Logger logger =
+            LoggerFactory.getLogger(AuthenticationServiceImpl.class);
+
     @Override
     public User login(String login, String password) throws AuthenticationException {
-        //TODO: add corresponding log message about method login was called
+        logger.debug("Method login was called. Params: login={}", login);
+
         User user = findByLogin(login);
+
         if (!user.getPassword().equals(password)) {
+            logger.warn("Invalid password for login={}", login);
             throw new AuthenticationException("Username or password are incorrect");
         }
+        logger.info("User successfully logged in. userId={}", user.getUserId());
         return user;
     }
 
     private User findByLogin(String login) {
         User user = new User(login, "1234");
-        // this user identifier should be set by DB. We will use dummy data for this example
         user.setUserId(2L);
         return user;
     }

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

@@ -4,16 +4,25 @@
 import java.util.List;
 import mate.academy.model.Order;
 import mate.academy.model.Product;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class OrderServiceImpl implements OrderService {
+    private static final Logger logger =
+            LoggerFactory.getLogger(OrderServiceImpl.class);
+
     @Override
     public Order completeOrder(Long userId) {
-        // TODO: add log message about method completeOrder was called
+        logger.info("Method completeOrder was called. Params: 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);
+
+        logger.info("Order completed successfully. orderId={}, userId={}",
+                order.getOrderId(), userId);
         return order;
     }
 
@@ -23,8 +32,12 @@ private List<Product> getAllProductsFromShoppingCart(Long userId) {
         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.debug("Products fetched from DB successfully. userId={}, count={}",
+                userId, products.size());
+
         return products;
     }
 }

src/main/resources/logback.xml

@@ -0,0 +1,21 @@
+<configuration>
+    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
+        <file>logs/app.log</file>
+        <append>true</append>
+        <encoder>
+            <pattern>%d{yyyy-MM-dd HH:mm:ss} [%level] [%thread] %logger{10} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss} [%level] %logger{10} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="debug">
+        <appender-ref ref="CONSOLE"/>
+        <appender-ref ref="FILE"/>
+    </root>
+
+</configuration>

target/checkstyle-cachefile

@@ -0,0 +1,11 @@
+#Thu Mar 19 16:09:00 CET 2026
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\Main.java=1773931834648
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\exception\\AuthenticationException.java=1773764970934
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\model\\Order.java=1773764970934
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\model\\Product.java=1773764970935
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\model\\User.java=1773764970936
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\service\\AuthenticationService.java=1773764970937
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\service\\AuthenticationServiceImpl.java=1773932366339
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\service\\OrderService.java=1773764970938
+C\:\\Users\\Admin\\IdeaProjects\\jv-logger\\src\\main\\java\\mate\\academy\\service\\OrderServiceImpl.java=1773932849902
+configuration*?=8630E6DC4E424D54441EA9302A85FDAA43E423CA