Hello,

I am working on a client/server app where the client retrieves a hibernate pojo by remotely invoking a retrieval
method of a session bean on the server. The problem that I am experiencing stems from an apparent error that occurs
during the deserialization of the resultant object on the client.

Caused by: java.io.InvalidClassException: org.hibernate.collection.AbstractPersistentCollection; local class incompatible: stream classdesc serialVersionUID = 7663409046372276524, local class serialVersionUID = -7982170513654570219

at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:519)

at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1546)


The Application Configuration is as follows:

JBoss 4.0.2
Java jdk1.5.0_03(Client and Server)
Hibernate 3
Postgres 7.4

It's also worth pointing out that the hibernate libraries are in the classpath of the Client.
Does anyone have a clue about what caused this problem and how to remedy it?
Any advice would be greatly appreciated.


Raoul

The compiler inserts a binary id for each .class . Even though object A and object B have the same name and properties, the ids may not be the same under certain situations. Has the interface of the class changed lately? If so, you may have to recompile distributes libs.

The class interfaces are the same on both client and server. In fact, if a non-persistent instance of the the POJO in question is returned(using new), the error doesn't occur. It appears, that Hibernate modifies the byte code of persistent objects, which might be the cause of this problem.

However, I'm performing a pretty basic task so I would be surprised if this issue hasn't already been addressed by the Hibernate community.

Raoul

Sorry to break it to you but this one of hibernates severe flaws. Basically,
hibernate bungs up the pojos with enhancements which effectively make it impossible to deserialize the object over rmi, since the classloader is expecting the objects in the original untainted form. I wonder if the hibernate team is aware of this issue.


Cheers,

Jake

Um. Right.

So how exactly do you propose to "fix" this "flaw", without requiring loading the entire database into memory before serializing?

I'm dying to know....

To the original poster. Make sure you have the same version of the Hibernate jar on both client and server, and it will all work perfectly. There is no problem deserializing objects as long as you have the hibernate.jar around.