Question

I’m trying to use JPA EntityManagerFactory bootstrapping without persistence.xml, which is new in Spring 3.1 (since M2), but it appears that spring is still searching for a persistence.xml file, despite the fact that packagesToScan is specified.

In context.xml, the entityManagerFactory is configured thusly:

<bean id="my-persistence-unit"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="persistenceProviderClass"
        value="org.hibernate.ejb.HibernatePersistence"/>
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
    </property>
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop>
        </props>
    </property>
    <property name="packagesToScan">
        <list>
            <value>my.package.name</value>
        </list>
    </property>
</bean>

But on application startup, a PersistenceException with message “Unable to resolve persistence unit root URL” occurs:

...
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'my-persistence-unit' defined in class path resource [META-INF/context.xml]: 
...
Caused by: javax.persistence.PersistenceException: Unable to resolve persistence unit root URL
        at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.determineDefaultPersistenceUnitRootUrl(DefaultPersistenceUnitManager.java:429)
        at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.preparePersistenceUnitInfos(DefaultPersistenceUnitManager.java:327)
        at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.afterPropertiesSet(DefaultPersistenceUnitManager.java:309)
        at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:209)
        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1504)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1442)
        ... 34 more 
Caused by: java.io.FileNotFoundException: class path resource [] cannot be resolved to URL because it does not exist
        at org.springframework.core.io.ClassPathResource.getURL(ClassPathResource.java:179)
        at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.determineDefaultPersistenceUnitRootUrl(DefaultPersistenceUnitManager.java:426)
        ... 40 more

Before I added packagesToScan, I had a minimal persistence.xml, and set the persistenceXmlLocation, like so:

<property name="persistenceXmlLocation"
    value="classpath:META-INF/persistence.xml"/>

which worked fine. So what am I doing incorrectly now?

edit added jpaVendorAdapter, error remains.

edit removed persistenceUnitName per a deleted comment; renamed beans to the persistence unit name (for @PersistenceContext)

update this error seems to depend upon which kind of application context loader is used. The code works in a spring/junit test via @ContextConfiguration, but not via ClassPathXmlApplicationContext

Answer 1

It’s a bug in Spring, I reported it.

Note that it happens only for a packaged application, when all classpath items are jars. That’s why it doesn’t fail in unit tests.