fixed all mistake.

pom.xml

@@ -3,11 +3,9 @@
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-
     <groupId>org.example</groupId>
     <artifactId>jv-jdbc-intro</artifactId>
     <version>1.0-SNAPSHOT</version>
-
     <properties>
         <jdk.version>17</jdk.version>
         <maven.compiler.source>17</maven.compiler.source>
@@ -16,7 +14,6 @@
         <maven.checkstyle.plugin.configLocation>
             https://raw.githubusercontent.com/mate-academy/style-guides/master/java/checkstyle.xml
         </maven.checkstyle.plugin.configLocation>
-
     </properties>
     <dependencies>
         <!-- https://mvnrepository.com/artifact/com.mysql/mysql-connector-j -->
@@ -25,10 +22,7 @@
             <artifactId>mysql-connector-j</artifactId>
             <version>8.3.0</version>
         </dependency>
-
-
     </dependencies>
-
     <build>
         <plugins>
             <plugin>

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

@@ -14,16 +14,17 @@ public static void main(String[] args) {
         BookDao bookDao = (BookDao) injector.getInstance(BookDao.class);
         Book book = new Book();
         book.setPrice(BigDecimal.valueOf(548));
-        book.setTitle("The Witcher. 1. The Last Wish");
+        book.setTitle("The Witcher.");
         bookDao.create(book);
         System.out.println(bookDao.findById(6L).orElseThrow(()
                 -> new RuntimeException("Can`t find book with id " + 1L)));
         List<Book> books = bookDao.findAll();
         books.forEach(System.out::println);
-        Optional<Book> newBook = bookDao.findById(6L);
+        Optional<Book> newBook = bookDao.findById(5L);
         Book newBookForChange = newBook.get();
         newBookForChange.setPrice(BigDecimal.valueOf(250));
+        newBookForChange.setTitle("Harry Potter");
         System.out.println(bookDao.update(newBook.get()));
-        System.out.println(bookDao.deleteById(7L));
+        System.out.println(bookDao.deleteById(5L));
     }
 }

src/main/java/mate/academy/dao/BookDaoImpl.java

@@ -9,36 +9,38 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import mate.academy.ConnectionUtil;
 import mate.academy.exception.DataProcessingException;
 import mate.academy.lib.Dao;
 import mate.academy.model.Book;
+import mate.academy.util.ConnectionUtil;
 
 @Dao
 public class BookDaoImpl implements BookDao {
+    private static void checkAffectedRows(int affectedRows) {
+        if (affectedRows < 1) {
+            throw new RuntimeException("Expected to update at least one row");
+        }
+    }
+
     @Override
     public Book create(Book book) {
         String sql = "INSERT INTO books (title, price) VALUES (?, ?)";
         try (Connection connection = ConnectionUtil.getConnection();
-                PreparedStatement statement = connection.prepareStatement(sql,
-                        Statement.RETURN_GENERATED_KEYS)) {
+                PreparedStatement statement = connection
+                        .prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
             statement.setString(1, book.getTitle());
             statement.setBigDecimal(2, book.getPrice());
-
             int affectedRows = statement.executeUpdate();
-            if (affectedRows < 1) {
-                throw new RuntimeException(
-                        "Expected to insert at least one row, but inserted 0 rows.");
-            }
+            checkAffectedRows(affectedRows);
             ResultSet generatedKeys = statement.getGeneratedKeys();
             if (generatedKeys.next()) {
                 Long id = generatedKeys.getObject(1, Long.class);
                 book.setId(id);
             }
+            return book;
         } catch (SQLException e) {
-            throw new DataProcessingException("Can`t add new car: " + book, e);
+            throw new DataProcessingException("Can't add new book: " + book, e);
         }
-        return book;
     }
 
     @Override
@@ -53,7 +55,8 @@ public Optional<Book> findById(Long id) {
                 return book;
             }
         } catch (SQLException e) {
-            throw new DataProcessingException("Can not create connection to the DB", e);
+            throw new DataProcessingException("Failed to establish a database connection. "
+                    + "Please check the database configuration and network connectivity.", e);
         }
         return Optional.empty();
     }
@@ -63,7 +66,7 @@ public List<Book> findAll() {
         String sql = "SELECT * FROM books";
         try (Connection connection = ConnectionUtil.getConnection();
                 Statement statement = connection.createStatement();
-                     ResultSet resultSet = statement.executeQuery(sql)) {
+                ResultSet resultSet = statement.executeQuery(sql)) {
             List<Book> books = new ArrayList<>();
             while (resultSet.next()) {
                 books.add(parseResultSet(resultSet));
@@ -80,7 +83,7 @@ public Book update(Book book) {
         String sql = "UPDATE books SET title = ?, price = ? WHERE id = ?";
         try (Connection connection = ConnectionUtil.getConnection();
                 PreparedStatement statement =
-                            connection.prepareStatement(sql)) {
+                        connection.prepareStatement(sql)) {
             statement.setString(1, book.getTitle());
             statement.setBigDecimal(2, book.getPrice());
             statement.setLong(3, book.getId());
@@ -97,8 +100,7 @@ public Book update(Book book) {
     public boolean deleteById(Long id) {
         String sql = "DELETE FROM books WHERE id = ?";
         try (Connection connection = ConnectionUtil.getConnection();
-                PreparedStatement statement
-                        = connection.prepareStatement(sql)) {
+                PreparedStatement statement = connection.prepareStatement(sql)) {
             statement.setLong(1, id);
             int affectedRows = statement.executeUpdate();
             checkAffectedRows(affectedRows);
@@ -122,10 +124,4 @@ private Book parseResultSet(ResultSet resultSet) {
             throw new DataProcessingException("Result set is empty", e);
         }
     }
-
-    private static void checkAffectedRows(int affectedRows) {
-        if (affectedRows < 1) {
-            throw new RuntimeException("Expected to update at least one row");
-        }
-    }
 }

src/main/java/mate/academy/ConnectionUtil.java → src/main/java/mate/academy/util/ConnectionUtil.java

@@ -1,15 +1,15 @@
-package mate.academy;
+package mate.academy.util;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.util.Properties;
 
 public class ConnectionUtil {
-    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";
+    private static final String DB_URL = "jdbc:mysql://localhost:3306/book_store";
     private static final Properties DB_PROPERTIES;
-    private static final String USER = "root";
-    private static final String PASSWORD = "1234";
+    private static final String USER = "****";
+    private static final String PASSWORD = "*******";
 
     static {
         DB_PROPERTIES = new Properties();

src/main/resources/init_db.sql

@@ -1,6 +1,6 @@
 CREATE TABLE books (
-    id INT NOT NULL  AUTO_INCREMENT,
-    title VARCHAR(255),
-    price DECIMAL,
+    id BIGINT NOT NULL AUTO_INCREMENT,
+    title VARCHAR(255) NOT NULL,
+    price DECIMAL(10, 2) NOT NULL,
     PRIMARY KEY (id)
-)
+);