Spring Scheduler - When there is a cyclic dependency, scheduled method doesn't start in transaction

Question

I am working on an application which is using Spring 3, Hibernate and JPA. I have two classes as follows:

@Component
class Manager {
    @Autowired
    Util util;
}

and

@Component
class Util {
    @Autowired
    Manager manager;

    @Scheduled(fixedDelay = 1 * 60 * 1000)
    @Transactional(propagation = Propagation.REQUIRED)
    public void scheduledMethod(){
        // Need to update the database in a transaction
    }
}

The relevant part from application context is as follows:

    <context:component-scan base-package="packageName" />
    <tx:annotation-driven />
    <bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
       <property name="persistenceUnitName" value="defaultPU" />
       <property name="dataSource" ref="dataSource" />
    </bean>
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
       <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>
    <task:annotation-driven executor="executor" scheduler="scheduler"/>
    <task:executor id="executor"
       pool-size="10"
       queue-capacity="10000"
       rejection-policy="CALLER_RUNS"/>
    <task:scheduler id="scheduler" pool-size="10"/>

With this configuration, I get the following exception

javax.persistence.TransactionRequiredException: no transaction is in progress
        at org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:978)
        at sun.reflect.GeneratedMethodAccessor88.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:365)
        at com.sun.proxy.$Proxy43.flush(Unknown Source)
        at sun.reflect.GeneratedMethodAccessor88.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
        at com.sun.proxy.$Proxy43.flush(Unknown Source)

If I remove the autowiring of Manager class from Util class, it works fine. Also, while debugging I found that the scheduled method starts executing even if there is some error in the application context file.

For some legacy reasons, I cannot avoid the cyclic dependency. Can someone help why this exception occurs in case of cyclic dependency?

Mckoy

It seems that scheduled postprocessor processes bare bean even if it's supposed to fire after AOP proxy creator(because postprocessors are ordered). I think you can send a bug to Spring JIRA, at least this behavior is poorly documentated. As a workaround you can fire transactional method from a separate bean with scheduled method or use TransactionTemplate instead if transactional. – Foreordination

Answer 1

You can achive this using @PostConstruct

@Component
class Manager {

    Util util;

    public void setUtil(Util util) {
        this.util =  util;
    }
}


@Component
class Util {
    @Autowired
    Manager manager;

    @PostConstruct
    public void init(){
        manager.setUtil(this);

    }

    @Scheduled(fixedDelay = 1 * 60 * 1000)
    @Transactional(propagation = Propagation.REQUIRED)
    public void scheduledMethod(){
        // Need to update the database in a transaction
    }
}

Goalie