Hiya,
If you look at the stack trace, you can see that the error is occuring when
the hashCode is being calculated for the StudyPageSet:
java.lang.NullPointerException
at com.voxsant.thinkscan.model.Study.hashCode(Study.java:211)
at
com.voxsant.thinkscan.model.StudyPageSet.hashCode(StudyPageSet.java:111)
I believe this is because at the point that StudyPageSet is trying to use
Study.name as part of its hashCode(), yet name has not yet been
deserialized.
Therefore I think that you need to supply overridden implementations of
readObject and writeObject, something like below so that name gets loaded
before the sets:
private void readObject(ObjectInputStream ois) throws
ClassNotFoundException, IOException {
name = (String) ois.readObject();
studyPageSets = (Set<StudyPageSet>) ois.readObject();
studyPages = (Set<StudyPages>) ois.readObject();
}
private void writeObject(ObjectOutputStream oos) throws IOException {
oos.writeObject(this.name);
oos.writeObject(this.studyPageSets);
oos.writeObject(this.studyPages);
}
Obviously these might not be the exact implementations that you want, but I
think you'll find that this is the approach to take if you need the Object
model exactly as it currently is.
Cheers,
Pete
On 9/18/07, adriel manalansan <[EMAIL PROTECTED]> wrote:
>
> I tried to delete the implementation of Serializable in my BaseModel,
> but still there is an error in my log file. The log error
>
> ERROR [main] ManagerBase.start(638) | Exception loading
> sessions from persistent storage
> java.lang.NullPointerException
>
> only occurs when I turn off tomcat then restart it again and refresh my
> page. the variable Study.name became null but before I restarted it has
> a value? How does this error occurs?
>
>
> Thanks,
> Adriel
>
> On Mon, 2007-09-17 at 11:20 -0300, Derek Broughton wrote:
> > adriel manalansan wrote:
> >
> > > Hello everybody,
> > >
> > > I think this is a stupid question but I really cant make it work. I am
> > > using appfuse 1.9.4 and webwork. In appfuse, it is default that
> > > BaseObject class implements java.io.Serializable. I have a superclass
> > > named BaseModel:
> > >
> > > public abstract class BaseModel extends BaseObject implements
> > > Serializable {
> >
> > Surely that's a subclass :-)
> >
> > If BaseObject _does_ implement Serializable (it certainly does in
> appfuse
> > 2.0), why do you need BaseModel to do so?
>
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