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Re: Please help..
On Thu, 24 Aug 2000, Tim Brown wrote:
> So, can we now change the design of an object currently stored in the server and
> expect it to work? I always thought you had to flush the database if you changed
> any of the objects.
As long as you give your classes a serialVersionUID you can change the classes
and use them together with object already stored in the database (by the former
version of the class). This is a feature of Java serialization. See
http://java.sun.com/products/jdk/1.2/docs/guide/serialization/spec/serialTOC.doc.html
for more information about that.
Falko
>
> Mahesh Halyal wrote:
>
> > Yes, the proxy class exists. Earlier
> > I used to get this error if I don't have the
> > Proxy class.
> >
> > Is this error dut to change in jre ?
> > Because earlier we had only jdk1.2.
> > Now we have installed jdk1.3 also
> > on our server and even IBM jikes.
> > But my PATH variables points
> > to jdk1.2. i.e when I execute "java -version"
> > it;s jdk1.2.2. But I suspect ozone might be taking
> > some other jre ( may be jikes ? ) internally.
> >
> > Did u have any problem due to the change in jre ?
> >
> > regards ,
> > Mahesh
> >
> > Falko Braeutigam wrote:
> >
> > > On Tue, 22 Aug 2000, Mahesh Halyal wrote:
> > > > Hello All :
> > > >
> > > > I am using ozone database. I have used
> > > > serialversionUID in my classes to take care
> > > > of versioning.
> > > >
> > > > So far everything was working fine. Many times
> > > > I have modified the object to be stored in database
> > > > by introducing new methods and variables.
> > > >
> > > > But now I am unable to read or write to database.
> > > > I am getting the following error message at my application side
> > > >
> > > > ---------------------------------------------------------------------------
> > > >
> > > > java.lang.ClassCastException: org.ozoneDB.OzoneProxy
> > > > ---------------------------------------------------------------------------
> > > >
> > > > On ozone side the error message is
> > > > ---------------------------------------------------------------------------
> > > >
> > > > warning: ObjectState: proxy(): unable to create proper proxy object.
> > > > ----------------------------------------------------------------------------
> > > >
> > > > I have done the "opp" also. ( earlier not doing "opp" after java
> > > > comiplation
> > > > used to give the this problem )
> > >
> > > It seems that the server cannot find the proxy class file for a specific
> > > class. Are you sure that the *_Proxy.class file exists and that the server can
> > > access it?
> > >
> > > Falko
> > > --
> > > ______________________________________________________________________
> > > Falko Braeutigam mailto:falko@smb-tec.com
> > > SMB GmbH http://www.smb-tec.com
>
> --
> Tim Brown
> URL: http://www.incenter.org
--
______________________________________________________________________
Falko Braeutigam mailto:falko@smb-tec.com
SMB GmbH http://www.smb-tec.com