Hibernate could not initialize proxy

Question

I'm getting the following exception..

SEVERE: Servlet.service() for servlet [appServlet] in context with path [/assessment] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: could not initialize proxy - no Session] with root cause
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:149)
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195)
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
    at org.assessme.com.entity.User_$$_javassist_0.getFirstName(User_$$_javassist_0.java)
    at org.assessme.com.UserManagementController.data(UserManagementController.java:40)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

The problem I'm pretty sure of is in my DAO...

public class UserDAO {

    public User getById(Long id) {
        HibernateUtil.buildSessionFactory();
        Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();
        User user = (User) session.load(User.class, id);
        session.getTransaction().commit();
        return user;
    }
}

Is this the correct way to handle the transactions? Should I do buildSessionFactory every time I want to return an object? Is it better to only do it once?

you should put session creation outside the method, even better if you could autowire session to the userDAO. — ant
– ant, Commented Apr 23, 2012 at 20:06
What method of transaction are you using? Do you have OpenSessionInViewFilter configured in web.xml? — nobeh
– nobeh, Commented Apr 23, 2012 at 20:09
Do you have any examples I could follow regarding the autowiring? Thank you for your advice :) — David
– David, Commented Apr 23, 2012 at 20:13
also - just to add, I already have the spring libs as I'm using it for SpringMVC, but I've not used any of the autowiring stuff yet. — David
– David, Commented Apr 23, 2012 at 20:18

Mahm00d · Accepted Answer · 2012-04-24 14:29:41Z

2

session.beginTransaction() returns the Transaction object, you should call the commit into that instance. You are handling two separate transactions in each session.getTransaction(). Also make sure you close the session (session.close()) in any place.

http://docs.jboss.org/hibernate/orm/3.5/reference/es-ES/html/example-weblog.html

edited Apr 24, 2012 at 14:29

Mahm00d

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answered Apr 23, 2012 at 20:12

Ignacio A. Poletti

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Comments

kyiu · Accepted Answer · 2012-04-23 20:08:18Z

1

Try

HibernateUtil.getSessionFactory().beginSession();

instead of ...getSessionFactory().getCurrentSession();

In your case, if no session has been previously created, you're not retrieving an active session.

answered Apr 23, 2012 at 20:08

kyiu

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