Example: how to start EclipseLink (or other JPA) transaction declaratively in Spring

Here is example of declarative transaction management with EclipseLink JPA provider in Spring-based application. Similar approach should work with other JPA providers as well.
I use Maven for building so these were the required dependencies:

 org.eclipse.persistence
 javax.persistence
 2.0.0


 org.aspectj
 aspectjrt
 1.6.9


 org.springframework
 spring-aspects
 3.0.4.RELEASE

Here is Spring's application context file:

  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xmlns:context="http://www.springframework.org/schema/context" 
  xmlns:aop="http://www.springframework.org/schema/aop" 
  xmlns:tx="http://www.springframework.org/schema/tx" 
  xsi:schemaLocation="http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
  http://www.springframework.org/schema/context
  http://www.springframework.org/schema/context/spring-context-3.0.xsd
  http://www.springframework.org/schema/aop
  http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
  http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd ">

  
  
  
  
  

  
   
  
  
    
    
  
  
   
   
  

Now inside of your.services.package you can have such class:

@Component //instantiate as Spring's bean
public class ProductServiceImpl implements ProductService {
 //Trick part #1 - Spring substitutes here entity manager 
 //and handles it in a way that each thread thinks he's the only one working with this manager.
 //For E.M. marked by this annotation declarative transaction management is possible
 @PersistenceContext(type = PersistenceContextType.TRANSACTION) 
 private EntityManager containerEm;

 //Trick part #2 - Spring wraps this method in transaction which is handled by containerEm
 @Transactional(readOnly=false, propagation=Propagation.REQUIRED)
 public void yourMethod() {
   ...
   //Here you can do whatever you want with E.M.:
   containerEm.createNativeQuery(...);
   //or
   em.persist(...);
   //etc.
   ...
 }//end of transactional method

}