Hibernate version:
3.0.5


I've recently upgraded to 3.0.5 from 2.1.8 and I'm running into LazyInitializationException on my web page that uses Struts...
It was working fine in 2.1.8, but I guess 3.0.5 now defaults the lazy initialization to be true which is causing a problem everytime it tries to render my jsp file being forwarded from the struts action.

So what are my choices to deal with this problem for Hibernate 3.0.5?

I researched the web, and some says use Spring framework, and others says to use Servlet Filters ....

I'm a bit lost as to what is the correct solution for dealing with this problem for Hibernate 3.0.5.

Also, if there is a way to change this default to false in a single place (maybe in the hibnerate configuration file?), please let me know as well. I have over 30+tables and to workaround by setting all of the columns to lazy=false would be lot of work ....

Please HELP!!!!

If you're not already using Spring, I wouldn't recommend you add it just to deal with this issue.

You can change this behavior at the class-level of each mapping file
<class name="MyObj" table="MYTBL" lazy="true" >

But it's definitely not recommended because that could cause queries to be run and data to be retrieved that isn't required or necessary.

I would suggest you look at using a ServletFilter to close your session. Check out this link for the Open Session in View pattern http://www.hibernate.org/43.html

You can set all the collections to null after loading the object from the session, before closing the session. This will prevent Lazy Initialization Exception.

But if you do need certain collections, then also call Hibernate.initialize(whatevrObject.getWhateverCollection()).
This will load the collection. This should be done before closing the session.

Hope this helps.

This is not good advice.


The solution is to have an explicit "assembly" phase, just like you would have if you were using EJB2+DTO, of to fetch all nedded data in the initial query using "left join fetch".

First, thank all for responding. I have further questions about "Open Session in View patter". (Please bare with me as I am a newbie in this area... )




I am starting to look into this, but can't figure out how to correctly fire the servletfilter.... I have specified the filter and filter-mapping in web.xml but doesn't seem to execut the doFilter code.

I copied HibernateFilter code and is correctly compiled into the classpath of the web server.

Here's what I did in web.xml

<filter>
<filter-name>hibernatefilter</filter-name>
<filter-class>HibernateFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>hibernatefilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
</filter-mapping>



..
09:43:43,968 ERROR LazyInitializationException:19 - could not initialize proxy - the owning Session was closed
org.hibernate.LazyInitializationException: could not initialize proxy - the owning Session was closed
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:53)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:84)
at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:134)
at com.adobe.automation.database.hibernate.TblProduct$$EnhancerByCGLIB$$d573865c.getTblProductConfiguration(<generated>)
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:585)
at org.apache.commons.el.ArraySuffix.evaluate(ArraySuffix.java:314)
at org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:145)
at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java:263)
at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java:190)
at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:920)
at org.apache.jsp.common_005fjsp.feathome_jsp._jspx_meth_c_forEach_0(org.apache.jsp.common_005fjsp.feathome_jsp:248)
at org.apache.jsp.common_005fjsp.feathome_jsp._jspService(org.apache.jsp.common_005fjsp.feathome_jsp:171)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
at javax.servlet.h

You know, the filter has an init() method. The most trivial debugging would involve maybe a System.out.println("HEY I'M RUNNING") in that method.

<filter>
<filter-name>HibernateFilter</filter-name>
<filter-class>my.package.HibernateFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>HibernateFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

Thanks, this worked. I was using apache common log, and it wasn't somehow showing it in the console.

I just have one more question.

Where do I find HibernateUtil code? This is mentioned in the "Open Session in View" doc. There is one exist in the Hibernate Tutorial but this done doesn't contain the transaction management...

Nevermind .... I found it from the link from "Open Session in View" page.

I would also recommend, if you're using Struts, to filter on the action Servlet and not on /*

This way, you are sure that the session is closed prior to returning to the Browser and also sure you don't close the session while forwarding or including a jsp.

Also, I found that with Struts at least, committing the transaction in the Filter was not helpful because if you received any kind of database exception you would no longer be able to display the message on the page where the exception occurred - say for a ConcurrentMod exception. Because by the time the Filter executes the commit, Struts has already forwarded you to another page.

I guess you are right .... This approach doesn't seem to work with Struts.
Well, I'll probably make everything non-lazy, or revert back to hibernate2 then....

NO!

It works fine. I'm doing it in a very large application. Just filter on the action, not on the JSP's.

And Struts has no interceptor or no way to hook into the processing?