2

After we migrate an application from JBoss 4 to JBoss 5 we are getting org.hibernate.LazyInitializationException when lazy loading is done using Bean-Managed Transaction (BMT) Session Beans.

I know it is a known issue when it comes to Web development but we are not doing lazy-loading from a Web component, we are doing it inside the Bean, in one single call.

If we change the bean to CMT everything works fine, but the production class is gigantic, and doing it might not be an option.

Why is it happening and what are the options to solve this problem?

BMT Stateless Session Bean

@Stateless
@TransactionManagement(TransactionManagementType.BEAN)
public class BMTBean implements BMTBeanLocal{

    @PersistenceContext
    private EntityManager em;

    @Override
    public void customerOperation() {

        Customer customer = em.find(Customer.class, 1);     
        List<Address> list = customer.getAddresses();       
        String streetName = list.get(0).getStreet(); // The error happens here!

        System.out.println("Street: " + streetName);
    }
}

Customer entity

@Entity
@Table
public class Customer {

    @Id
    @Column
    private Integer id;

    @Column
    private String name;

    @OneToMany(fetch=FetchType.LAZY, mappedBy="customer")   
    private List<Address> addresses;

}

Address entity which is lazy loaded

@Entity
@Table
public class Address {

    @Id
    @Column
    private Integer id;

    @Column
    private String street;

    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="CUSTOMER_ID", insertable = false, updatable = false)
    private Customer customer;

}

Detailed Exception

13:12:45,374 ERROR [LazyInitializationException] failed to lazily initialize a collection of role: entity.Customer.addresses, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: entity.Customer.addresses, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
    at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365)
    at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
    at org.hibernate.collection.PersistentBag.get(PersistentBag.java:445)
    at bean.BMTBean.customerOperation(BMTBean.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeTarget(MethodInvocation.java:122)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:111)
    at org.jboss.ejb3.EJBContainerInvocationWrapper.invokeNext(EJBContainerInvocationWrapper.java:69)
    at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.invoke(InterceptorSequencer.java:73)
    at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.aroundInvoke(InterceptorSequencer.java:59)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.aop.advice.PerJoinpointAdvice.invoke(PerJoinpointAdvice.java:174)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.fillMethod(InvocationContextInterceptor.java:72)
    at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_fillMethod_328422269.invoke(InvocationContextInterceptor_z_fillMethod_328422269.java)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.setup(InvocationContextInterceptor.java:88)
    at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_setup_328422269.invoke(InvocationContextInterceptor_z_setup_328422269.java)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:62)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:56)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.StatelessBMTInterceptor.handleInvocation(StatelessBMTInterceptor.java:106)
    at org.jboss.ejb3.tx.BMTInterceptor.invoke(BMTInterceptor.java:55)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:68)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:176)
    at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:216)
    at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:207)
    at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:164)
    at com.sun.proxy.$Proxy492.customerOperation(Unknown Source)
    at servlets.BMTServlet.doGet(BMTServlet.java:29)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:662)
13:12:45,376 ERROR [[BMTServlet]] Servlet.service() for servlet BMTServlet threw exception
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: entity.Customer.addresses, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
    at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365)
    at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
    at org.hibernate.collection.PersistentBag.get(PersistentBag.java:445)
    at bean.BMTBean.customerOperation(BMTBean.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeTarget(MethodInvocation.java:122)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:111)
    at org.jboss.ejb3.EJBContainerInvocationWrapper.invokeNext(EJBContainerInvocationWrapper.java:69)
    at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.invoke(InterceptorSequencer.java:73)
    at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.aroundInvoke(InterceptorSequencer.java:59)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.aop.advice.PerJoinpointAdvice.invoke(PerJoinpointAdvice.java:174)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.fillMethod(InvocationContextInterceptor.java:72)
    at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_fillMethod_328422269.invoke(InvocationContextInterceptor_z_fillMethod_328422269.java)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.setup(InvocationContextInterceptor.java:88)
    at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_setup_328422269.invoke(InvocationContextInterceptor_z_setup_328422269.java)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:62)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:56)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.StatelessBMTInterceptor.handleInvocation(StatelessBMTInterceptor.java:106)
    at org.jboss.ejb3.tx.BMTInterceptor.invoke(BMTInterceptor.java:55)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:68)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67)
    at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
    at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:176)
    at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:216)
    at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:207)
    at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:164)
    at com.sun.proxy.$Proxy492.customerOperation(Unknown Source)
    at servlets.BMTServlet.doGet(BMTServlet.java:29)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:662)
Evandro Pomatti
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    These are only narrow snippets. Where is a transaction started/stopped? Probably there is no transaction - at that point the em.find() still works but the returned entity is automatically unmanaged and hence your lazy init error. The difference in execution between JBoss 4/5 is likely then a difference in Hibernate version and lazy loading strategy. It was always wrong, but you just didn't suffer from it until now because Hibernate just happened to automatically load the addresses collection. – Gimby Jan 12 '15 at 16:57
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    @Gimby Transaction is not started manually. The system just call the Bean method from within a CMT SFSB without a transaction. Yet, the `find()` works ok, all non-lazy data is returned. The problem happens in the lazy-loading only. I would expect both to work or none, since both are just selects, yet the lazy-loading is the one that will not work. – Evandro Pomatti Jan 13 '15 at 12:32

1 Answers1

2

LazyInitializationException happens when you did not load a relationship of the class and try to access it.

Imagine the class:

@Entity
public class Person {
    @OneToOne
    private Dog dog;

    @OneToMany
    private List<Email> emailList;
}

When you load Person from the database two things will happen:

  1. dog will be loaded by default
  2. emailList will not be loaded by default

The error that you received is because your addresses is not loaded. The JPA rule is:

  1. Every relationship that finishes with "*One" will be loaded by default, it is defined as EAGER
  2. Every relationship that finishes with "*Many" will NOT be loaded by default, it is defined as LAZY

What is Lazy? Lazy means that the relationship will only be loaded after the attribute is accessed. When you do person.getEmailList() the JPA will look for an connection to get the EmailList from the database.

The problem is: what happen if the connection is closed? You will get the error LazyInitializationException.

How to solve it? You have some options:

  1. You can create a query: select p from Person p left join fetch p.emailList e. Like this the JPA will load the email list
  2. You could change the relationship annotation: @OneToMany(fetch = FetchType.EAGER). With this configuration the JPA will always load the relationship. The problem with this approach is that you will always load it. If you have a long list but want only to access the person.name() that could reduce your project perfomance.

  3. Keep your connection opened: it would be like:

    // open the connection // get the entity // access the list // close the conection

    The problem with this approach is that if you forget to close the connection you will have an leak of resources. Other problem with this approach is that you will have the N+1 effect. N+1 is when your system is able to do several requests to the database.

  4. Use the OpenSessionInView pattern. Works like the option 3, but you will have a global handler for the request. You will have a Filter that will handle the connection.

If you want more info about N+1 of this error take a look at this link: http://uaihebert.com/four-solutions-to-the-lazyinitializationexception/

uaiHebert
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  • If the SB uses BMT then why I am able to execute the first `find()` anyway? I understand the concept of lazy-loading but how it interacts with the manual transactions is the tricky part at this moment. The answer for this is "Hibernate does not create new sessions for lazy operations inside a BMT Session Bean"? – Evandro Pomatti Jan 13 '15 at 12:21
  • If you are using BMT, no. With find your requested the action. The spec says that for a JSE project the Implementation may open the transaction automatically, but not for the JEE. – uaiHebert Jan 13 '15 at 14:56
  • That seems to be the cause. I wasn't able to to find what you said on the specification doc, I appreciate if you could share the reference. But in practice it seems that Hibernate won't handle transaction when lazy-loading, I need to do it "na unha". Thank you! – Evandro Pomatti Jan 13 '15 at 17:06