Merge pull request #45 from eugenp/master

update
2020-04-15 21:36:24 +02:00
parent f7522a1bb9 23099cff16
commit 13ce413ed2
177 changed files with 4601 additions and 173 deletions
@@ -0,0 +1,4 @@
+### Relevant Articles:
+
+- [Boruvka’s Algorithm for Minimum Spanning Trees](https://www.baeldung.com/java-boruvka-algorithm)
+- [Gradient Descent in Java](https://www.baeldung.com/java-gradient-descent)
@@ -0,0 +1,7 @@
+## Atomikos
+
+This module contains articles about Atomikos
+
+### Relevant Articles: 
+
+- [Guide Transactions Using Atomikos]()
@@ -0,0 +1,119 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>atomikos</artifactId>
+	<name>atomikos</name>
+
+	<parent>
+		<groupId>com.baeldung</groupId>
+		<artifactId>parent-modules</artifactId>
+		<version>1.0.0-SNAPSHOT</version>
+	</parent>
+
+	<dependencies>
+		<dependency>
+			<groupId>com.atomikos</groupId>
+			<artifactId>transactions-jdbc</artifactId>
+			<version>${atomikos-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.atomikos</groupId>
+			<artifactId>transactions-jms</artifactId>
+			<version>${atomikos-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.atomikos</groupId>
+			<artifactId>transactions-hibernate4</artifactId>
+			<version>${atomikos-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-context</artifactId>
+			<version>${spring-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-tx</artifactId>
+			<version>${spring-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.data</groupId>
+			<artifactId>spring-data-jpa</artifactId>
+			<version>1.11.23.RELEASE</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-test</artifactId>
+			<version>${spring-version}</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.hibernate</groupId>
+			<artifactId>hibernate-entitymanager</artifactId>
+			<version>${hibernate.version}</version>
+			<scope>provided</scope>
+			<exclusions>
+				<exclusion>
+					<groupId>javax.transaction</groupId>
+					<artifactId>jta</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.activemq</groupId>
+			<artifactId>activemq-core</artifactId>
+			<version>5.7.0</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.derby</groupId>
+			<artifactId>derby</artifactId>
+			<version>10.8.1.2</version>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+			<scope>test</scope>
+		</dependency>
+		<!-- the JTA API -->
+		<dependency>
+			<groupId>javax.transaction</groupId>
+			<artifactId>jta</artifactId>
+			<version>1.1</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.geronimo.specs</groupId>
+			<artifactId>geronimo-jta_1.0.1B_spec</artifactId>
+			<version>1.0</version>
+		</dependency>
+		<dependency>
+			<groupId>javax.validation</groupId>
+			<artifactId>validation-api</artifactId>
+			<version>2.0.1.Final</version>
+		</dependency>
+		<dependency>
+			<groupId>org.hibernate.validator</groupId>
+			<artifactId>hibernate-validator</artifactId>
+			<version>6.1.2.Final</version>
+		</dependency>
+		<dependency>
+			<groupId>javax.el</groupId>
+			<artifactId>javax.el-api</artifactId>
+			<version>3.0.0</version>
+		</dependency>
+		<dependency>
+			<groupId>org.glassfish.web</groupId>
+			<artifactId>javax.el</artifactId>
+			<version>2.2.4</version>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<atomikos-version>5.0.6</atomikos-version>
+		<spring-version>5.1.6.RELEASE</spring-version>
+		<hibernate.version>5.4.3.Final</hibernate.version>
+	</properties>
+
+</project>
@@ -0,0 +1,53 @@
+package com.baeldung.atomikos.direct;
+
+import java.sql.Connection;
+import java.sql.Statement;
+import java.util.UUID;
+
+import javax.sql.DataSource;
+
+import com.atomikos.icatch.jta.UserTransactionImp;
+
+public class Application {
+
+    private DataSource inventoryDataSource;
+    private DataSource orderDataSource;
+
+    public Application(DataSource inventoryDataSource, DataSource orderDataSource) {
+        this.inventoryDataSource = inventoryDataSource;
+        this.orderDataSource = orderDataSource;
+    }
+
+    public void placeOrder(String productId, int amount) throws Exception {
+
+        UserTransactionImp utx = new UserTransactionImp();
+        String orderId = UUID.randomUUID()
+            .toString();
+        boolean rollback = false;
+        try {
+            utx.begin();
+            Connection inventoryConnection = inventoryDataSource.getConnection();
+            Connection orderConnection = orderDataSource.getConnection();
+            Statement s1 = inventoryConnection.createStatement();
+            String q1 = "update Inventory set balance = balance - " + amount + " where productId ='" + productId + "'";
+            s1.executeUpdate(q1);
+            s1.close();
+            Statement s2 = orderConnection.createStatement();
+            String q2 = "insert into Orders values ( '" + orderId + "', '" + productId + "', " + amount + " )";
+            s2.executeUpdate(q2);
+            s2.close();
+            inventoryConnection.close();
+            orderConnection.close();
+        } catch (Exception e) {
+            System.out.println(e.getMessage());
+            rollback = true;
+        } finally {
+            if (!rollback)
+                utx.commit();
+            else
+                utx.rollback();
+        }
+
+    }
+
+}
@@ -0,0 +1,41 @@
+package com.baeldung.atomikos.spring;
+
+import java.sql.Connection;
+import java.sql.Statement;
+import java.util.UUID;
+
+import javax.sql.DataSource;
+
+import org.springframework.transaction.annotation.Transactional;
+
+public class Application {
+
+    private DataSource inventoryDataSource;
+    private DataSource orderDataSource;
+
+    public Application(DataSource inventoryDataSource, DataSource orderDataSource) {
+        this.inventoryDataSource = inventoryDataSource;
+        this.orderDataSource = orderDataSource;
+    }
+
+    @Transactional(rollbackFor = Exception.class)
+    public void placeOrder(String productId, int amount) throws Exception {
+
+        String orderId = UUID.randomUUID()
+            .toString();
+        Connection inventoryConnection = inventoryDataSource.getConnection();
+        Connection orderConnection = orderDataSource.getConnection();
+        Statement s1 = inventoryConnection.createStatement();
+        String q1 = "update Inventory set balance = balance - " + amount + " where productId ='" + productId + "'";
+        s1.executeUpdate(q1);
+        s1.close();
+        Statement s2 = orderConnection.createStatement();
+        String q2 = "insert into Orders values ( '" + orderId + "', '" + productId + "', " + amount + " )";
+        s2.executeUpdate(q2);
+        s2.close();
+        inventoryConnection.close();
+        orderConnection.close();
+
+    }
+
+}
@@ -0,0 +1,68 @@
+package com.baeldung.atomikos.spring.config;
+
+import java.util.Properties;
+
+import javax.transaction.SystemException;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+import org.springframework.transaction.jta.JtaTransactionManager;
+
+import com.atomikos.icatch.jta.UserTransactionManager;
+import com.atomikos.jdbc.AtomikosDataSourceBean;
+import com.baeldung.atomikos.spring.Application;
+
+@Configuration
+@EnableTransactionManagement
+public class Config {
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public AtomikosDataSourceBean inventoryDataSource() {
+        AtomikosDataSourceBean dataSource = new AtomikosDataSourceBean();
+        dataSource.setLocalTransactionMode(true);
+        dataSource.setUniqueResourceName("db1");
+        dataSource.setXaDataSourceClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
+        Properties xaProperties = new Properties();
+        xaProperties.put("databaseName", "db1");
+        xaProperties.put("createDatabase", "create");
+        dataSource.setXaProperties(xaProperties);
+        dataSource.setPoolSize(10);
+        return dataSource;
+    }
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public AtomikosDataSourceBean orderDataSource() {
+        AtomikosDataSourceBean dataSource = new AtomikosDataSourceBean();
+        dataSource.setLocalTransactionMode(true);
+        dataSource.setUniqueResourceName("db2");
+        dataSource.setXaDataSourceClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
+        Properties xaProperties = new Properties();
+        xaProperties.put("databaseName", "db2");
+        xaProperties.put("createDatabase", "create");
+        dataSource.setXaProperties(xaProperties);
+        dataSource.setPoolSize(10);
+        return dataSource;
+    }
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public UserTransactionManager userTransactionManager() throws SystemException {
+        UserTransactionManager userTransactionManager = new UserTransactionManager();
+        userTransactionManager.setTransactionTimeout(300);
+        userTransactionManager.setForceShutdown(true);
+        return userTransactionManager;
+    }
+
+    @Bean
+    public JtaTransactionManager jtaTransactionManager() throws SystemException {
+        JtaTransactionManager jtaTransactionManager = new JtaTransactionManager();
+        jtaTransactionManager.setTransactionManager(userTransactionManager());
+        jtaTransactionManager.setUserTransaction(userTransactionManager());
+        return jtaTransactionManager;
+    }
+
+    @Bean
+    public Application application() {
+        return new Application(inventoryDataSource(), orderDataSource());
+    }
+}
@@ -0,0 +1,48 @@
+package com.baeldung.atomikos.spring.jpa;
+
+import java.util.Set;
+import java.util.UUID;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.Validator;
+import javax.validation.ValidatorFactory;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.baeldung.atomikos.spring.jpa.inventory.Inventory;
+import com.baeldung.atomikos.spring.jpa.inventory.InventoryRepository;
+import com.baeldung.atomikos.spring.jpa.order.Order;
+import com.baeldung.atomikos.spring.jpa.order.OrderRepository;
+
+public class Application {
+
+    @Autowired
+    private InventoryRepository inventoryRepository;
+
+    @Autowired
+    private OrderRepository orderRepository;
+
+    @Transactional(rollbackFor = Exception.class)
+    public void placeOrder(String productId, int amount) throws Exception {
+
+        String orderId = UUID.randomUUID()
+            .toString();
+        Inventory inventory = inventoryRepository.findOne(productId);
+        inventory.setBalance(inventory.getBalance() - amount);
+        inventoryRepository.save(inventory);
+        Order order = new Order();
+        order.setOrderId(orderId);
+        order.setProductId(productId);
+        order.setAmount(new Long(amount));
+        ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
+        Validator validator = factory.getValidator();
+        Set<ConstraintViolation<Order>> violations = validator.validate(order);
+        if (violations.size() > 0)
+            throw new Exception("Invalid instance of an order.");
+        orderRepository.save(order);
+
+    }
+
+}
@@ -0,0 +1,38 @@
+package com.baeldung.atomikos.spring.jpa.config;
+
+import javax.transaction.SystemException;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+import org.springframework.transaction.jta.JtaTransactionManager;
+
+import com.atomikos.icatch.jta.UserTransactionManager;
+import com.baeldung.atomikos.spring.jpa.Application;
+
+@Configuration
+@EnableTransactionManagement
+public class Config {
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public UserTransactionManager userTransactionManager() throws SystemException {
+        UserTransactionManager userTransactionManager = new UserTransactionManager();
+        userTransactionManager.setTransactionTimeout(300);
+        userTransactionManager.setForceShutdown(true);
+        return userTransactionManager;
+    }
+
+    @Bean
+    public JtaTransactionManager transactionManager() throws SystemException {
+        JtaTransactionManager jtaTransactionManager = new JtaTransactionManager();
+        jtaTransactionManager.setTransactionManager(userTransactionManager());
+        jtaTransactionManager.setUserTransaction(userTransactionManager());
+        return jtaTransactionManager;
+    }
+
+    @Bean
+    public Application application() {
+        return new Application();
+    }
+
+}
@@ -0,0 +1,31 @@
+package com.baeldung.atomikos.spring.jpa.inventory;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "INVENTORY")
+public class Inventory {
+
+    @Id
+    private String productId;
+    private Long balance;
+
+    public String getProductId() {
+        return productId;
+    }
+
+    public void setProductId(String productId) {
+        this.productId = productId;
+    }
+
+    public Long getBalance() {
+        return balance;
+    }
+
+    public void setBalance(Long balance) {
+        this.balance = balance;
+    }
+
+}
@@ -0,0 +1,53 @@
+package com.baeldung.atomikos.spring.jpa.inventory;
+
+import java.util.Properties;
+
+import javax.persistence.EntityManagerFactory;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
+
+import com.atomikos.jdbc.AtomikosDataSourceBean;
+
+@Configuration
+@EnableJpaRepositories(basePackages = "com.baeldung.atomikos.spring.jpa.inventory", entityManagerFactoryRef = "inventoryEntityManager", transactionManagerRef = "transactionManager")
+public class InventoryConfig {
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public AtomikosDataSourceBean inventoryDataSource() {
+        AtomikosDataSourceBean dataSource = new AtomikosDataSourceBean();
+        dataSource.setLocalTransactionMode(true);
+        dataSource.setUniqueResourceName("db1");
+        dataSource.setXaDataSourceClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
+        Properties xaProperties = new Properties();
+        xaProperties.put("databaseName", "db1");
+        xaProperties.put("createDatabase", "create");
+        dataSource.setXaProperties(xaProperties);
+        dataSource.setPoolSize(10);
+        return dataSource;
+    }
+
+    @Bean
+    public EntityManagerFactory inventoryEntityManager() {
+        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
+        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
+        factory.setJpaVendorAdapter(vendorAdapter);
+        factory.setPackagesToScan("com.baeldung.atomikos.spring.jpa.inventory");
+        factory.setDataSource(inventoryDataSource());
+        Properties jpaProperties = new Properties();
+        //jpaProperties.put("hibernate.show_sql", "true");
+        //jpaProperties.put("hibernate.format_sql", "true");
+        jpaProperties.put("hibernate.dialect", "org.hibernate.dialect.DerbyDialect");
+        jpaProperties.put("hibernate.current_session_context_class", "jta");
+        jpaProperties.put("javax.persistence.transactionType", "jta");
+        jpaProperties.put("hibernate.transaction.manager_lookup_class", "com.atomikos.icatch.jta.hibernate3.TransactionManagerLookup");
+        jpaProperties.put("hibernate.hbm2ddl.auto", "create-drop");
+        factory.setJpaProperties(jpaProperties);
+        factory.afterPropertiesSet();
+        return factory.getObject();
+    }
+
+}
@@ -0,0 +1,9 @@
+package com.baeldung.atomikos.spring.jpa.inventory;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface InventoryRepository extends JpaRepository<Inventory, String> {
+
+}
@@ -0,0 +1,42 @@
+package com.baeldung.atomikos.spring.jpa.order;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.validation.constraints.Max;
+
+@Entity
+@Table(name = "ORDERS")
+public class Order {
+
+    @Id
+    private String orderId;
+    private String productId;
+    @Max(5)
+    private Long amount;
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(String orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getProductId() {
+        return productId;
+    }
+
+    public void setProductId(String productId) {
+        this.productId = productId;
+    }
+
+    public Long getAmount() {
+        return amount;
+    }
+
+    public void setAmount(Long amount) {
+        this.amount = amount;
+    }
+
+}
@@ -0,0 +1,53 @@
+package com.baeldung.atomikos.spring.jpa.order;
+
+import java.util.Properties;
+
+import javax.persistence.EntityManagerFactory;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
+
+import com.atomikos.jdbc.AtomikosDataSourceBean;
+
+@Configuration
+@EnableJpaRepositories(basePackages = "com.baeldung.atomikos.spring.jpa.order", entityManagerFactoryRef = "orderEntityManager", transactionManagerRef = "transactionManager")
+public class OrderConfig {
+
+    @Bean(initMethod = "init", destroyMethod = "close")
+    public AtomikosDataSourceBean orderDataSource() {
+        AtomikosDataSourceBean dataSource = new AtomikosDataSourceBean();
+        dataSource.setLocalTransactionMode(true);
+        dataSource.setUniqueResourceName("db2");
+        dataSource.setXaDataSourceClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
+        Properties xaProperties = new Properties();
+        xaProperties.put("databaseName", "db2");
+        xaProperties.put("createDatabase", "create");
+        dataSource.setXaProperties(xaProperties);
+        dataSource.setPoolSize(10);
+        return dataSource;
+    }
+
+    @Bean
+    public EntityManagerFactory orderEntityManager() {
+        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
+        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
+        factory.setJpaVendorAdapter(vendorAdapter);
+        factory.setPackagesToScan("com.baeldung.atomikos.spring.jpa.order");
+        factory.setDataSource(orderDataSource());
+        Properties jpaProperties = new Properties();
+        //jpaProperties.put("hibernate.show_sql", "true");
+        //jpaProperties.put("hibernate.format_sql", "true");
+        jpaProperties.put("hibernate.dialect", "org.hibernate.dialect.DerbyDialect");
+        jpaProperties.put("hibernate.current_session_context_class", "jta");
+        jpaProperties.put("javax.persistence.transactionType", "jta");
+        jpaProperties.put("hibernate.transaction.manager_lookup_class", "com.atomikos.icatch.jta.hibernate3.TransactionManagerLookup");
+        jpaProperties.put("hibernate.hbm2ddl.auto", "create-drop");
+        factory.setJpaProperties(jpaProperties);
+        factory.afterPropertiesSet();
+        return factory.getObject();
+    }
+
+}
@@ -0,0 +1,9 @@
+package com.baeldung.atomikos.spring.jpa.order;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface OrderRepository extends JpaRepository<Order, String> {
+
+}
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>
@@ -0,0 +1,10 @@
+CREATE TABLE INVENTORY (
+    productId VARCHAR PRIMARY KEY,
+    balance INT
+);
+
+CREATE TABLE ORDERS (
+    orderId VARCHAR PRIMARY KEY,
+    productId VARCHAR,
+    amount INT NOT NULL CHECK (amount <= 5)
+);
@@ -0,0 +1 @@
+com.atomikos.icatch.file=logs
@@ -0,0 +1,118 @@
+package com.baeldung.atomikos.direct;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Properties;
+import java.util.UUID;
+
+import javax.sql.DataSource;
+
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import com.atomikos.icatch.jta.UserTransactionImp;
+import com.atomikos.jdbc.AtomikosDataSourceBean;
+
+public class ApplicationUnitTest {
+
+    private static DataSource inventoryDataSource;
+    private static DataSource orderDataSource;
+
+    private static String productId = UUID.randomUUID()
+        .toString();
+
+    @Test
+    @Ignore
+    public void testPlaceOrderSuccess() throws Exception {
+        int amount = 1;
+        long initialBalance = getBalance(inventoryDataSource, productId);
+        Application application = new Application(inventoryDataSource, orderDataSource);
+        application.placeOrder(productId, amount);
+        long finalBalance = getBalance(inventoryDataSource, productId);
+        assertEquals(initialBalance - amount, finalBalance);
+    }
+
+    @Test
+    @Ignore
+    public void testPlaceOrderFailure() throws Exception {
+        int amount = 10;
+        long initialBalance = getBalance(inventoryDataSource, productId);
+        Application application = new Application(inventoryDataSource, orderDataSource);
+        application.placeOrder(productId, amount);
+        long finalBalance = getBalance(inventoryDataSource, productId);
+        assertEquals(initialBalance, finalBalance);
+    }
+
+    @BeforeClass
+    public static void setUp() throws SQLException {
+
+        inventoryDataSource = getDataSource("db1");
+        orderDataSource = getDataSource("db2");
+        Connection inventoryConnection = inventoryDataSource.getConnection();
+        Connection orderConnection = orderDataSource.getConnection();
+        String createInventoryTable = "create table Inventory ( " + " productId VARCHAR ( 100 ) PRIMARY KEY, balance INT )";
+        String createInventoryRow = "insert into Inventory values ( '" + productId + "', 10000 )";
+        Statement s1 = inventoryConnection.createStatement();
+        try {
+            s1.executeUpdate(createInventoryTable);
+        } catch (Exception e) {
+            System.out.println("Inventory table exists");
+        }
+        try {
+            s1.executeUpdate(createInventoryRow);
+        } catch (Exception e) {
+            System.out.println("Product row exists");
+        }
+        s1.close();
+        String createOrderTable = "create table Orders ( orderId VARCHAR ( 100 ) PRIMARY KEY, productId VARCHAR ( 100 ), amount INT NOT NULL CHECK (amount <= 5) )";
+        Statement s2 = orderConnection.createStatement();
+        try {
+            s2.executeUpdate(createOrderTable);
+        } catch (Exception e) {
+            System.out.println("Orders table exists");
+        }
+        s2.close();
+        inventoryConnection.close();
+        orderConnection.close();
+    }
+
+    private static DataSource getDataSource(String db) {
+
+        DataSource ds;
+        AtomikosDataSourceBean ads = new AtomikosDataSourceBean();
+        ads.setXaDataSourceClassName("org.apache.derby.jdbc.EmbeddedXADataSource");
+        Properties properties = new Properties();
+        properties.put("databaseName", db);
+        properties.put("createDatabase", "create");
+        ads.setXaProperties(properties);
+        ads.setUniqueResourceName(db);
+        ads.setPoolSize(10); // optional
+        ads.setBorrowConnectionTimeout(10); // optional
+        ds = ads;
+        return ds;
+
+    }
+
+    private static long getBalance(DataSource inventoryDataSource, String productId) throws Exception {
+
+        UserTransactionImp utx = new UserTransactionImp();
+        utx.begin();
+        Connection inventoryConnection = inventoryDataSource.getConnection();
+        Statement s1 = inventoryConnection.createStatement();
+        String q1 = "select balance from Inventory where productId='" + productId + "'";
+        ResultSet rs1 = s1.executeQuery(q1);
+        if (rs1 == null || !rs1.next())
+            throw new Exception("Product not found: " + productId);
+        long balance = rs1.getLong(1);
+        inventoryConnection.close();
+        utx.commit();
+        return balance;
+
+    }
+
+}
@@ -0,0 +1,108 @@
+package com.baeldung.atomikos.spring;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.UUID;
+
+import javax.sql.DataSource;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.baeldung.atomikos.spring.config.Config;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { Config.class })
+public class ApplicationUnitTest {
+
+    private static String productId = UUID.randomUUID()
+        .toString();
+
+    @Autowired
+    Application application;
+
+    @Autowired
+    DataSource inventoryDataSource;
+
+    @Autowired
+    DataSource orderDataSource;
+
+    @Test
+    @Ignore
+    public void testPlaceOrderSuccess() throws Exception {
+        int amount = 1;
+        long initialBalance = getBalance(inventoryDataSource, productId);
+        application.placeOrder(productId, amount);
+        long finalBalance = getBalance(inventoryDataSource, productId);
+        assertEquals(initialBalance - amount, finalBalance);
+    }
+
+    @Test
+    @Ignore
+    public void testPlaceOrderFailure() throws Exception {
+        int amount = 10;
+        long initialBalance = getBalance(inventoryDataSource, productId);
+        try {
+            application.placeOrder(productId, amount);
+        } catch (Exception e) {
+            System.out.println(e.getMessage());
+        }
+        long finalBalance = getBalance(inventoryDataSource, productId);
+        assertEquals(initialBalance, finalBalance);
+    }
+
+    @Before
+    public void setUp() throws SQLException {
+
+        Connection inventoryConnection = inventoryDataSource.getConnection();
+        Connection orderConnection = orderDataSource.getConnection();
+        String createInventoryTable = "create table Inventory ( " + " productId VARCHAR ( 100 ) PRIMARY KEY, balance INT )";
+        String createInventoryRow = "insert into Inventory values ( '" + productId + "', 10000 )";
+        Statement s1 = inventoryConnection.createStatement();
+        try {
+            s1.executeUpdate(createInventoryTable);
+        } catch (Exception e) {
+            System.out.println("Inventory table exists");
+        }
+        try {
+            s1.executeUpdate(createInventoryRow);
+        } catch (Exception e) {
+            System.out.println("Product row exists");
+        }
+        s1.close();
+        String createOrderTable = "create table Orders ( orderId VARCHAR ( 100 ) PRIMARY KEY, productId VARCHAR ( 100 ), amount INT NOT NULL CHECK (amount <= 5) )";
+        Statement s2 = orderConnection.createStatement();
+        try {
+            s2.executeUpdate(createOrderTable);
+        } catch (Exception e) {
+            System.out.println("Orders table exists");
+        }
+        s2.close();
+        inventoryConnection.close();
+        orderConnection.close();
+    }
+
+    private static long getBalance(DataSource inventoryDataSource, String productId) throws Exception {
+
+        Connection inventoryConnection = inventoryDataSource.getConnection();
+        Statement s1 = inventoryConnection.createStatement();
+        String q1 = "select balance from Inventory where productId='" + productId + "'";
+        ResultSet rs1 = s1.executeQuery(q1);
+        if (rs1 == null || !rs1.next())
+            throw new Exception("Product not found: " + productId);
+        long balance = rs1.getLong(1);
+        inventoryConnection.close();
+        return balance;
+
+    }
+
+}
@@ -0,0 +1,80 @@
+package com.baeldung.atomikos.spring.jpa;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.sql.SQLException;
+import java.util.UUID;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.baeldung.atomikos.spring.jpa.config.Config;
+import com.baeldung.atomikos.spring.jpa.inventory.Inventory;
+import com.baeldung.atomikos.spring.jpa.inventory.InventoryConfig;
+import com.baeldung.atomikos.spring.jpa.inventory.InventoryRepository;
+import com.baeldung.atomikos.spring.jpa.order.OrderConfig;
+import com.baeldung.atomikos.spring.jpa.order.OrderRepository;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { Config.class, InventoryConfig.class, OrderConfig.class })
+public class ApplicationUnitTest {
+
+    private static String productId = UUID.randomUUID()
+        .toString();
+
+    @Autowired
+    Application application;
+
+    @Autowired
+    InventoryRepository inventoryRepository;
+
+    @Autowired
+    OrderRepository orderRepository;
+
+    @Test
+    @Ignore
+    public void testPlaceOrderSuccess() throws Exception {
+        int amount = 1;
+        long initialBalance = getBalance(inventoryRepository, productId);
+        application.placeOrder(productId, amount);
+        long finalBalance = getBalance(inventoryRepository, productId);
+        assertEquals(initialBalance - amount, finalBalance);
+    }
+
+    @Test
+    @Ignore
+    public void testPlaceOrderFailure() throws Exception {
+        int amount = 10;
+        long initialBalance = getBalance(inventoryRepository, productId);
+        try {
+            application.placeOrder(productId, amount);
+        } catch (Exception e) {
+            System.out.println(e.getMessage());
+        }
+        long finalBalance = getBalance(inventoryRepository, productId);
+        assertEquals(initialBalance, finalBalance);
+    }
+
+    @Before
+    public void setUp() throws SQLException {
+
+        Inventory inventory = new Inventory();
+        inventory.setProductId(productId);
+        inventory.setBalance(new Long(10000));
+        inventoryRepository.save(inventory);
+
+    }
+
+    private static long getBalance(InventoryRepository inventoryRepository, String productId) throws Exception {
+
+        return inventoryRepository.findOne(productId)
+            .getBalance();
+
+    }
+
+}
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>
@@ -0,0 +1 @@
+com.atomikos.icatch.file=logs
@@ -0,0 +1,110 @@
+package com.baeldung.stringtoint
+
+import org.junit.Test
+
+import java.text.DecimalFormat
+
+import static org.junit.Assert.assertEquals
+import static org.junit.Assert.assertNull
+
+class ConvertStringToInt {
+
+    @Test
+    void givenString_whenUsingAsInteger_thenConvertToInteger() {
+        def stringNum = "123"
+        def invalidString = "123a"
+        Integer expectedInteger = 123
+        Integer integerNum = stringNum as Integer
+        def intNum = invalidString?.isInteger() ? invalidString as Integer : null
+
+        assertNull(null, intNum)
+        assertEquals(integerNum, expectedInteger)
+    }
+
+    @Test
+    void givenString_whenUsingAsInt_thenConvertToInt() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = stringNum as int
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingToInteger_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = stringNum.toInteger()
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingParseInt_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = Integer.parseInt(stringNum)
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingValueOf_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = Integer.valueOf(stringNum)
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingIntValue_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = new Integer(stringNum).intValue()
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingNewInteger_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        int intNum = new Integer(stringNum)
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test
+    void givenString_whenUsingDecimalFormat_thenConvertToInteger() {
+        def stringNum = "123"
+        int expectedInt = 123
+        DecimalFormat decimalFormat = new DecimalFormat("#")
+        int intNum = decimalFormat.parse(stringNum).intValue()
+
+        assertEquals(intNum, expectedInt)
+    }
+
+    @Test(expected = NumberFormatException.class)
+    void givenInvalidString_whenUsingAs_thenThrowNumberFormatException() {
+        def invalidString = "123a"
+        invalidString as Integer
+    }
+
+    @Test(expected = NullPointerException.class)
+    void givenNullString_whenUsingToInteger_thenThrowNullPointerException() {
+        def invalidString = null
+        invalidString.toInteger()
+    }
+
+    @Test
+    void givenString_whenUsingIsInteger_thenCheckIfCorrectValue() {
+        def invalidString = "123a"
+        def validString = "123"
+        def invalidNum = invalidString?.isInteger() ? invalidString as Integer : false
+        def correctNum = validString?.isInteger() ? validString as Integer : false
+
+        assertEquals(false, invalidNum)
+        assertEquals(123, correctNum)
+    }
+}
@@ -7,3 +7,4 @@ This module contains articles about Java 14.
 - [Guide to the @Serial Annotation in Java 14](https://www.baeldung.com/java-14-serial-annotation)
 - [Java Text Blocks](https://www.baeldung.com/java-text-blocks)
 - [Pattern Matching for instanceof in Java 14](https://www.baeldung.com/java-pattern-matching-instanceof)
+- [Helpful NullPointerExceptions in Java 14](https://www.baeldung.com/java-14-nullpointerexception)
@@ -4,7 +4,6 @@ This module contains articles about Map data structures in Java.

 ### Relevant Articles: 
 - [Guide to the Guava BiMap](https://www.baeldung.com/guava-bimap)
- [A Guide to Java HashMap](https://www.baeldung.com/java-hashmap)
 - [A Guide to LinkedHashMap in Java](https://www.baeldung.com/java-linked-hashmap)
 - [A Guide to TreeMap in Java](https://www.baeldung.com/java-treemap)
 - [How to Store Duplicate Keys in a Map in Java?](https://www.baeldung.com/java-map-duplicate-keys)
@@ -10,4 +10,5 @@ This module contains articles about advanced topics about multithreading with co
 - [Guide to RejectedExecutionHandler](https://www.baeldung.com/java-rejectedexecutionhandler)
 - [Guide to Work Stealing in Java](https://www.baeldung.com/java-work-stealing)
 - [Asynchronous Programming in Java](https://www.baeldung.com/java-asynchronous-programming)
+- [Java Thread Deadlock and Livelock](https://www.baeldung.com/java-deadlock-livelock)
 - [[<-- previous]](/core-java-modules/core-java-concurrency-advanced-2)
@@ -8,4 +8,5 @@ This module contains articles about basic Java concurrency
 - [Difference Between Wait and Sleep in Java](https://www.baeldung.com/java-wait-and-sleep)
 - [Guide to the Synchronized Keyword in Java](https://www.baeldung.com/java-synchronized)
 - [Life Cycle of a Thread in Java](https://www.baeldung.com/java-thread-lifecycle)
- [[<-- Prev]](/core-java-modules/core-java-concurrency-basic)
+- [Guide to AtomicMarkableReference](https://www.baeldung.com/java-atomicmarkablereference)
+- [[<-- Prev]](/core-java-modules/core-java-concurrency-basic)
@@ -1,26 +0,0 @@
-*.class
-
-0.*
-
-#folders#
-/target
-/neoDb*
-/data
-/src/main/webapp/WEB-INF/classes
-*/META-INF/*
-.resourceCache
-
-# Packaged files #
-*.jar
-*.war
-*.ear
-
-# Files generated by integration tests
-*.txt
-backup-pom.xml
-/bin/
-/temp
-
-#IntelliJ specific
-.idea/
-*.iml
@@ -1,93 +1,93 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-	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>
-	<artifactId>core-java-concurrency-testing</artifactId>
-	<version>0.1.0-SNAPSHOT</version>
-	<name>core-java-concurrency-testing</name>
-	<packaging>jar</packaging>
+    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>
+    <artifactId>core-java-concurrency-testing</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-concurrency-testing</name>
+    <packaging>jar</packaging>

-	<parent>
-		<groupId>com.baeldung</groupId>
-		<artifactId>parent-java</artifactId>
-		<version>0.0.1-SNAPSHOT</version>
-		<relativePath>../../parent-java</relativePath>
-	</parent>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
 	
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<version>4.13</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>com.googlecode.thread-weaver</groupId>
-			<artifactId>threadweaver</artifactId>
-			<version>0.2</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>com.google.code.tempus-fugit</groupId>
-			<artifactId>tempus-fugit</artifactId>
-			<version>1.1</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>com.googlecode.multithreadedtc</groupId>
-			<artifactId>multithreadedtc</artifactId>
-			<version>1.01</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.openjdk.jcstress</groupId>
-			<artifactId>jcstress-core</artifactId>
-			<version>0.5</version>
-		</dependency>
-	</dependencies>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.googlecode.thread-weaver</groupId>
+            <artifactId>threadweaver</artifactId>
+            <version>0.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.tempus-fugit</groupId>
+            <artifactId>tempus-fugit</artifactId>
+            <version>1.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.googlecode.multithreadedtc</groupId>
+            <artifactId>multithreadedtc</artifactId>
+            <version>1.01</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jcstress</groupId>
+            <artifactId>jcstress-core</artifactId>
+            <version>0.5</version>
+        </dependency>
+    </dependencies>

-	<build>
-		<plugins>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-compiler-plugin</artifactId>
-				<version>3.1</version>
-				<configuration>
-					<compilerVersion>${javac.target}</compilerVersion>
-					<source>${javac.target}</source>
-					<target>${javac.target}</target>
-				</configuration>
-			</plugin>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.1</version>
+                <configuration>
+                    <compilerVersion>${javac.target}</compilerVersion>
+                    <source>${javac.target}</source>
+                    <target>${javac.target}</target>
+                </configuration>
+            </plugin>

-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-shade-plugin</artifactId>
-				<version>2.2</version>
-				<executions>
-					<execution>
-						<id>main</id>
-						<phase>package</phase>
-						<goals>
-							<goal>shade</goal>
-						</goals>
-						<configuration>
-							<finalName>jcstress</finalName>
-							<transformers>
-								<transformer
-									implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
-									<mainClass>org.openjdk.jcstress.Main</mainClass>
-								</transformer>
-								<transformer
-									implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
-									<resource>META-INF/TestList</resource>
-								</transformer>
-							</transformers>
-						</configuration>
-					</execution>
-				</executions>
-			</plugin>
-		</plugins>
-	</build>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>2.2</version>
+                <executions>
+                    <execution>
+                        <id>main</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <finalName>jcstress</finalName>
+                            <transformers>
+                                <transformer
+                                    implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>org.openjdk.jcstress.Main</mainClass>
+                                </transformer>
+                                <transformer
+                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
+                                    <resource>META-INF/TestList</resource>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>

 </project>
@@ -7,4 +7,5 @@ This module contains articles about date operations in Java.
 - [Checking If Two Java Dates Are on the Same Day](https://www.baeldung.com/java-check-two-dates-on-same-day)
 - [Converting Java Date to OffsetDateTime](https://www.baeldung.com/java-convert-date-to-offsetdatetime)
 - [How to Set the JVM Time Zone](https://www.baeldung.com/java-jvm-time-zone)
+- [How to determine day of week by passing specific date in Java?](https://www.baeldung.com/java-get-day-of-week)
 - [[<-- Prev]](/core-java-modules/core-java-date-operations-1)
--- a/Show More
+++ b/Show More