Understanding how nested Spring @Transactional works

Question

I'm porting an EJB application to Spring and I'm facing some issues. The application is running in standalone (that's why we choose spring) with eclipselink.

In this application I need to create an Order, for which I first need to create a Customer, the OrderLines and then add a Payment for this Order.

The problem is that I want to do all the insertion in a single Transaction so that if the payment fails to be persisted nothing must be persisted. I tried to achieve this but it looks like I'm spanning multiple independent transaction because in case of failure data are persisted to th DB (ex: payment fails, customer is created anyway).

Here is the entry point :

public static void main(String[] args) {
    AbstractApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "applicationContext.xml" });
    BeanFactory beanFactory = (BeanFactory) context;
    MyService service = beanFactory.getBean(MyService.class);
    service.getNewOrders(true);
}

Here is the bean I'm resolving (using beanFactory.getBean) :

@Component
@Scope("prototype")
public class MyService {

    @Autowired
    private CustomerService customerService;

    @Autowired
    private OrderService orderService;

    @Autowired
    private PaymentService paymentService;

    @Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
    public void getNewOrders(boolean formattedOutput) {
        try {
            List<RawData> rawData = // Acquire data from a remote web service (http rest based)

            for (RawData data : rawData) {
                try {
                    this.handleOrder(data);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    private Order handleOrder(RawData rawData) throws Exception {
        Customer customer = new Customer();
        // Fill customer with rawData
        this.customerService.create(customer);

        Order order = new Order();
        order.setCustomer(customer);
        // Fill order with rawData
        this.orderService.create(order);

        Payment payment = new Payment();
        payment.setOrder(order);
        // Fill payment with rawData
        this.paymentService.create(payment);

        return order;
    }
}

Each service looks like the following :

@Service
@Transactional
public class CustomerService {

    @Autowired
    private CustomerDao customerDao;

    public void create(Customer customer) {
        // some works on customer fields (checking values etc)
        this.customerDao.create(customer);
    }
}

Which are all backed by a Dao :

@Repository
public class CustomerDao {

    @PersistenceContext
    protected EntityManager em;

    public void create(Customer customer) {
        this.em.persist(customer);
    }
}

Here are a few dependencies from maven pom.xml :

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>3.2.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>3.2.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.2.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>3.2.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>3.2.3.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>com.jolbox</groupId>
        <artifactId>bonecp</artifactId>
        <version>0.8.0-rc1</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.25</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>eclipselink</artifactId>
        <version>2.3.2</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>javax.persistence</artifactId>
        <version>2.0.3</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
        <version>2.3.2</version>
    </dependency>

Here is the persistence.xml :

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <shared-cache-mode>NONE</shared-cache-mode>
        <properties>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/db" />
            <property name="javax.persistence.jdbc.user" value="root" />
            <property name="javax.persistence.jdbc.password" value="" />
        </properties>
    </persistence-unit>
</persistence>

The spring configuration is the following :

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

    <bean id="myDataSource" class="com.jolbox.bonecp.BoneCPDataSource" destroy-method="close">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/db" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>

    <bean id="myEmf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="myDataSource" />
        <property name="jpaPropertyMap">
            <map>
                <entry key="eclipselink.weaving" value="false" />
            </map>
        </property>
    </bean>

    <bean id="myTxManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="myEmf" />
    </bean>

    <tx:annotation-driven transaction-manager="myTxManager" />

    <context:component-scan base-package="com.application" />

</beans>

EDIT

Added the creation of the ApplicationContext from the main, and an omitted method from MyService.java

Answer 1

How can you call the service method since it's private? It should be public. Private methods can't be intercepted by the Spring transactional interceptor, and can't be overridden by the CGLib dynamic proxy.

EDIT: OK, it's the usual problem. You're calling, from the main method, the method getNewOrders(), which is public and transactional. The Spring interceptor intercepts this method call. Since there is no transaction and the method is marked as SUPPORTS, Spring doesn't start any transaction.

Then this method calls the private handleOrder() method. Note that not only the method is private, which makes it impossible for Spring to intercept the method call, but the call is from a method in a component to a method in the same component. So even is the method was public, Spring could not intercept this method call. The transactional handling is proxy-based:

method --> transactional proxy --> Spring bean 1 --> transactional proxy --> Spring bean2

In this case, since you're not calling a method of another component, there is no proxy interception, and no transaction is started.

method --> transactional proxy --> Spring bean 1 --> transactional proxy --> Spring bean2
                                      ^   |
                                      |___|

So, what you have to do is

• create another Spring bean 'OrderHandler, for example)
• move the handleOrder() method to this Spring bean, make it public
• inject OrderHandler in MyService

And it will work fine.

This is explained in details in the Spring documentation.