Transactions and JPA / Persistence.xml

Question

I am having problems with transactions using the Hibernate implementation of JPA (I follow the Camel Example>

I am using the Hibernate JPA implementation:

<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-entitymanager</artifactId>
  <version>4.3.5.Final</version>
</dependency>

If I include the persistence.xml file in the META-INF folder, everything works fine:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             version="1.0">
  <persistence-unit name="tracer" transaction-type="RESOURCE_LOCAL">
    <class>org.apache.camel.processor.interceptor.jpa.JpaTraceEventMessage</class>
    <properties>
      <property name="hibernate.dialect" value="..."/>
      <property name="hibernate.connection.driver_class" value="..."/>
      <property name="hibernate.connection.url" value="..."/>
      <property name="hibernate.hbm2ddl.auto" value="create"/>
      <property name="hibernate.connection.username" value="..." />
      <property name="hibernate.connection.password" value="..."/>
    </properties>
  </persistence-unit>
</persistence>

I want to use the Java method, so I delete persistence.xml and create the following beans:

@Configuration
@EnableTransactionManagement
public class AppConfiguration
{
      @Bean public EntityManagerFactory entMngFac()
      {
        EntityManagerFactory emf  = Persistence.createEntityManagerFactory("tracer");
        return emf;
      }
      @Bean public DataSource ds()
      {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("...");
        dataSource.setUrl("...");
        dataSource.setUsername( "..." );
        dataSource.setPassword( "..." );
        return dataSource;
      }
      @Bean public PlatformTransactionManager ptm(EntityManagerFactory emf, DataSource ds)
      {
        JpaTransactionManager jpat = new JpaTransactionManager();
        jpat.setDataSource(ds);
        jpat.setEntityManagerFactory(emf);
        return jpat;
      }
      @Bean public TransactionTemplate tranTemp(PlatformTransactionManager ptm)
      {
        TransactionTemplate tt = new TransactionTemplate();
        tt.setTransactionManager(ptm);
        return tt;
      }
}

After saving, when Camel tries to reset the created JPATracer object, I get the following exception:

javax.persistence.TransactionRequiredException: no transaction is in progress
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.checkTransactionNeeded(AbstractEntityManagerImpl.java:1171)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:1332)
    at org.apache.camel.component.jpa.JpaProducer$1.doInTransaction(JpaProducer.java:86)

Which is a bit strange, since the error “no transaction” comes from the doInTransaction method.

My thoughts are that Camel starts a transaction and then Hibernate tries to clear the object and is not aware of the transaction Camel started? So there is some kind of mixture of transactions, but I can't figure out where.

Answer 1

EntityManagerFactory ( packagesToScan)

@Bean
public EntityManagerFactory entityManagerFactory() {
   LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
   em.setDataSource(ds());
   em.setPackagesToScan(new String[] { "org.apache.camel.processor.interceptor.jpa" });
   JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
   em.setJpaVendorAdapter(vendorAdapter);
   return em.getObject();
}