[hibernate-issues] [Hibernate-JIRA] Commented: (HBX-964) add serialVersionUID to entity classes

[Andrew Redhead (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HBX-964?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_27532 ] 

Andrew Redhead commented on HBX-964:
------------------------------------

Maybe "implements Serializable" should be removed by default and then when people actually want to implement Serializable they can make their own templates (and choose to add serialVersionUID support if they want, making that support as complicated as they like) ?

I've run into some situations where you do not want Serializable on your entities, these include:

1) If your mappings include lazy-loading, serialising an object over to a remote jvm will lead to the dreaded "LIE" unless you've put some thought into making sure the lazy relationships are pre-initialised before serialisation (thought which might not take place if the entities are just generated for you)

2) If your entities AREN'T serializable then you can get the Corba support in the Sun JDK to generate the stubs for your enties - which makes interoperating with .Net apps easy(ier) and avoids messing about with all sorts of type confusion with web-services

3) If you are putting your entities into the JBoss POJO treecache and you want to be sure that you are using the field level replication then not having Serializable on your entities means that if the cache falls back on using java serialisation then the "not serializable" stack trace will let you know about it

4) I guess a contentious suggestion - If you are using shared classloading between your "application tier" and your "presentation tier" and "call by reference" rather than strict jee comliant "call by value" then there is no need for serialisation at all...

I don't think that these cases form a compelling argument for removing Serializable support but I really dont think the default templates should make much effort to support it.

Cheers,

Andy

> add serialVersionUID to entity classes
> --------------------------------------
>
>                 Key: HBX-964
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HBX-964
>             Project: Hibernate Tools
>          Issue Type: Improvement
>          Components: hbm2java
>    Affects Versions: 3.2beta10
>            Reporter: Dan Allen
>            Priority: Minor
>         Attachments: HBX-964-v1.txt
>
>   Original Estimate: 5 minutes
>  Remaining Estimate: 5 minutes
>
> The serialVersionUID is recommended for classes that implement java.io.Serializable.  The hbm2java task should either set the serialVersionUID to 1L or automatically generate a value. I prefer setting it to 1L because it is easy and it will work, but if you feel motivated, you can look at what Eclipse does to generate this value from the class signature.
> I have included a patch that just sets it to 1L.

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