[jira] [Commented] (MYFACES-3306) + JPA with Hibernate creates Hibernate PersistentCollection where it should not. Causes

["Michael Kurz (JIRA)" <de...@myfaces.apache.org>]

    [ https://issues.apache.org/jira/browse/MYFACES-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13104566#comment-13104566 ] 

Michael Kurz commented on MYFACES-3306:
---------------------------------------

There might be a simpler solution. Try to add

<f:attribute name="collectionType" value="java.util.HashSet"/>

as a child to <h:selectManyCheckBox>.

> <h:selectManyCheckBox> + JPA with Hibernate creates Hibernate PersistentCollection where it should not. Causes 
> ---------------------------------------------------------------------------------------------------------------
>
>                 Key: MYFACES-3306
>                 URL: https://issues.apache.org/jira/browse/MYFACES-3306
>             Project: MyFaces Core
>          Issue Type: Bug
>          Components: General
>    Affects Versions: 2.1.2
>         Environment: JPA with Hibernate + Spring
>            Reporter: Kristian Jörg
>   Original Estimate: 24h
>  Remaining Estimate: 24h
>
> I have a case where I use a JPA domain object (Mission) that has a standard @ManyToMany relationship to another domain object Departments. The fetch type is set to EAGER on both ends.
> The web page has a <h:selectManyCheckBox> with all possible Departments. The selection is then mapped to the mission object's department set via a custom converter. This all works well.
> When I submit my form I get an org.hibernate.LazyInitializationException in (I believe)  the validation phase. The problem is that MyFaces tries to create a new instance of the specific hibernate class PersistentSet (which should NOT be used outside Hibernate). It then populates this Set with objects and that is when LazyInitializationException hits!
> I have pinpointed the exact location to org.apache.myfaces.shared_impl.renderkit.SharedRendererUtils.java, Line 255:
>                            // try to create the (concrete) collection from modelType 
>                             // or with the class object of componentValue (if any)
>                             try
>                             {
>                             	 targetForConvertedValues = (componentValue != null
>                                          ? componentValue.getClass()
>                                          : modelType).newInstance();
>                             }
> With I add a check so we are not instanciating Hibernate collections (AbstractPersistentCollection) the program then goes on to create a standard HashSet and all is well. My program works perfectly with this patch:
>                            // try to create the (concrete) collection from modelType 
>                             // or with the class object of componentValue (if any)
>                             try
>                             {
>                             	 targetForConvertedValues = (componentValue != null && !(componentValue instanceof org.hibernate.collection.AbstractPersistentCollection)
>                                          ? componentValue.getClass()
>                                          : modelType).newInstance();
>                             }
> Of course, adding a dependency on Hibernate in Myfaces is not the correct solution, so another solution has to be invented. 
> My program is solid in itself with regards to the dreaded LIE exception, it is only when I use persisted objects with OneToMany or ManyToMany collections that this problem occurs. 
> MyFaces should never try to instanciate Hibernate collections without having an entity manager session, which you do not.
> I can attach some code examples if needed, but the problem lies not in the rather standard JSF code, but in this specific point in code listed above. Let me know if more examples are needed.

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