Issue with lazy loading and Hibernate.initialize();

Question

I have a Order class containing a lazily loaded property List<OrderItem>. I need to keep it lazily loaded. In one case, I am loading all orders via Spring JPARepository:

@org.springframework.transaction.annotation.Transactional;
protected void doThingsWithOrderItems() {
    List<Order> orders = orderRepository.findAll();
    for (Order order : orders) {
        Hibernate.initialize(orders.getOrderItems());
        // do things with orders and their order items
    }
}

The previous method is called in the @PostConstruct method of a @Configuration class

My issue is that I get:

ERROR 15580 --- [           main] o.s.boot.SpringApplication               : Application startup failed

org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) ~[spring-context-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at com.lh.application.MyApplication.main(MyApplication.java:10) [classes/:na]
Caused by: org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:123) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.<init>(TomcatEmbeddedServletContainer.java:84) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getTomcatEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:554) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:179) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:164) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:134) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    ... 8 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initSettingsConfigurator': Invocation of init method failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.lh.application.entity.Order.OrderItems, could not initialize proxy - no Session
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:137) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:409) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1620) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:372) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.boot.web.servlet.ServletContextInitializerBeans.getOrderedBeansOfType(ServletContextInitializerBeans.java:234) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.web.servlet.ServletContextInitializerBeans.getOrderedBeansOfType(ServletContextInitializerBeans.java:215) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addServletContextInitializerBeans(ServletContextInitializerBeans.java:91) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.web.servlet.ServletContextInitializerBeans.<init>(ServletContextInitializerBeans.java:79) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.getServletContextInitializerBeans(EmbeddedWebApplicationContext.java:241) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.selfInitialize(EmbeddedWebApplicationContext.java:228) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.access$000(EmbeddedWebApplicationContext.java:89) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext$1.onStartup(EmbeddedWebApplicationContext.java:213) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatStarter.onStartup(TomcatStarter.java:55) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5196) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_91]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_91]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_91]
    at java.lang.Thread.run(Thread.java:745) ~[na:1.8.0_91]
Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.lh.application.entity.Order.orderItems, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:587) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:204) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:566) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:135) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.collection.internal.PersistentSet.iterator(PersistentSet.java:163) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at com.lh.application.entity.Order.doThingsWithOrderItem(Order.java:206) ~[classes/:na]
    at com.lh.application.config.InitSettingsConfigurator.doThingsWithOrderItems(InitSettingsConfigurator.java:169) ~[classes/:na]
    at com.lh.application.config.InitSettingsConfigurator.init(InitSettingsConfigurator.java:159) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:311) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:134) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    ... 34 common frames omitted

I am within a @Transactional method and, according to previous related questions and answers, I would expect my solution to work. What's wrong?

You're probably not really inside a transactional method. Probably because you didn't inject your transactional spring bean, but instead used new to create it. Post the relevant code. Also post the complete stack trace, as code (and not as a quote as you've done) — JB Nizet, Nov 05 '17 at 10:39
Look like you're trying to call transactional method while bean is being constructed. This answer may help https://stackoverflow.com/a/18790494/1654233. — yegodm, Nov 05 '17 at 10:49

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

Most likely you call doThingsWithOrderItems via this reference which is basically an invocation of the method on a non-proxied object. In order for Spring to create a proxy you should use a so-called self-injection pattern:

@Component
public class YourBean {

    @Autowire
    private YourBean yourBean;
    
    @PostConstruct
    private init(){
        yourBean.doThingsWithOrderItems();
    }

    @org.springframework.transaction.annotation.Transactional;
    public void doThingsWithOrderItems() {
        List<Order> orders = orderRepository.findAll();
        for (Order order : orders) {
            Hibernate.initialize(orders.getOrderItems());
            // do things with orders and their order items
        }
    }
}

Note that self-injection in Spring Framework may not work prior to version 4.3.

One more (and probably preferable) way to solve this problem is to extract your transactional method into a separated bean. In most cases, it will give you a cleaner code which is easier to test (because it's always easier and better to mock a dependency than making partials mocks via @Spy in Mockito).

It would be clearer if another bean called this method in its init method. — JB Nizet, Nov 05 '17 at 11:27
Yeah, agree. Moreover, it would be more testable as it's easier to mock that another bean. Will update my answer. — Danylo Zatorsky, Nov 05 '17 at 11:30

Issue with lazy loading and Hibernate.initialize();

1 Answers1