[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-6880) Implementations of org.hibernate.type.Type contain references to non-serializable entities

[Mindaugas Žakšauskas (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-6880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=44830#comment-44830 ] 

Mindaugas Žakšauskas commented on HHH-6880:
-------------------------------------------

Q: When you mention that types hold reference to Session, I assume you just mistyped and meant to say SessionFactory...
A: Yes, my bad. I meant {{o.h.e.SessionFactoryImplementor}} interface and its implementation, {{o.h.i.SessionFactoryImpl}}.

Q: Do you have a test case actually showing this?
A: Not really, as the real world scenario involves two different hosts and fat layer of configuration (including caching). It is however quite evident if you look at the source code of {{o.h.t.ComponentType}} or the others I mentioned.

I appreciate your efforts trying to solve this, but I don't think this solution is good enough. Reasons:
- We do not want to bind {{SessionFactory}} to JNDI and the option for avoiding this is only available in Hibernate v4. For most enterprises, upgrading such a major library to a .0 version is not really an option.
- You have not commented on my proposition to remove {{ComponentType.typeScope}} (and others) or at least make it {{transient}}. If an attribute is not used at all, why bother with serialization of something that is totally unnecessary? For the scenario which is driven by this issue (serializing cache keys and sending them over the network), speed is the key!!!
- You have not responded/haven't done any action with regards to the last issue I mentioned (comparator at {{org.hibernate.type.SortedSetType}} and {{org.hibernate.type.SortedMapType}}).

> Implementations of org.hibernate.type.Type contain references to non-serializable entities
> ------------------------------------------------------------------------------------------
>
>                 Key: HHH-6880
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-6880
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.6.7
>         Environment: Seen this on MySQL but I believe this is environment-agnostic
>            Reporter: Mindaugas Žakšauskas
>            Assignee: Steve Ebersole
>            Priority: Critical
>              Labels: serialization
>          Time Spent: 59m
>
> This is a spin-off from
> - https://forum.hibernate.org/viewtopic.php?f=1&t=1013687&sid=e62b8ea711e4986a6ff419e3e641e2e8
> - http://stackoverflow.com/q/8404559/7345
> org.hibernate.cache.CacheKey is an object which is used for L2 cache notifications - e.g. to flush a cache on a different cluster node when a certain object has been updated.
> The problem comes from org.hibernate.cache.CacheKey carrying the type which (sometimes) happens to have a reference to objects like org.hibernate.impl.SessionFactoryImpl.
> This problem is actually not just theoretic but also causes real pain. First, it takes much longer to broadcast cache flush events. Secondly, I get this exception during deserialization of such a CacheKey: 
> java.lang.NullPointerException
>  at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768)
>  at org.hibernate.impl.SessionFactoryObjectFactory.getNamedInstance(SessionFactoryObjectFactory.java:159)
>  at org.hibernate.impl.SessionFactoryImpl.readResolve(SessionFactoryImpl.java:753)
>  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 java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1061)
>  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1762)
>  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
>  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
>  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
>  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
>  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
>  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
>  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
>  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
>  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
>  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>  at java.io.ObjectInputStream.readUnshared(ObjectInputStream.java:441)
>  at my.class.deserializeKey(EhcacheUtils.java:35)
> I have done a quick scan through all the types, and found these problems related to their serializability:
> 1) org.hibernate.type.CollectionType, org.hibernate.type.ComponentType and subclasses of both - they use attribute "typeScope" (of type TypeFactory.TypeScope) which is assigned in the constructor and kept in the but seems to be never used. The typeScope in turn has a reference to the SessionImpl. Can it simply be removed?
> 2) org.hibernate.type.EntityType (and its subclasses) stores typeScope and only uses it in the getter, so I guess it should be safe to remove it, too.
> 3) org.hibernate.type.SortedSetType and org.hibernate.type.SortedMapType keeps a reference to the comparator, but does not enforce its serializability. It should at least throw a runtime exception in org.hibernate.mapping.Collection::getComparator if the comparator is not serializable.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira