Component class should be serializable meaning

[kenfrommera]

Hello,

I have very simple component which is used in order to retrieve current user. Its code is very simple:

package myApp.web.profile;

import org.jboss.seam.Component;
... other Seam imports ...
import org.jboss.seam.security.management.JpaIdentityStore;

import myApp.core.entity.auth.MyAppUser;

@Name("currentUser")
@AutoCreate
@Scope(ScopeType.SESSION)
@Restrict("#{identity.loggedIn}")
public class CurrentUser {

    @In
    private JpaIdentityStore identityStore;

    @In
    private Identity identity;

    @Unwrap
    public MyAppUser getMyAppUser() {
        String userLogin = identity.getPrincipal().getName();
        return (MyAppUser) identityStore.lookupUser(userLogin);
    }

    public static final MyAppUser instance() {
        return (MyAppUser) Component.getInstance(CurrentUser.class);
    }

}

Everything work fine with this component except that

WARN  [Component] Component class should be serializable: currentUser

is displayed when JBoss starts.

Can anyone explain this warning meaning?

[tmalatinszki]

It means that Your class should implement Serializable interface.
Just change class header to:

public class CurrentUser implements Serializable{

     private static final long serialVersionUID = 1L;

and the warning will disappear.

Regards,
Tamas

[kenfrommera]

Yes, but I wan to know why it is required for this component and not required for others.

Is it because this component has @Scope(ScopeType.SESSION)?

[tmalatinszki]

As far as I know it usually depends on the context where do you want to use Your components. I You want You can ignore all of these warnings, but don't forget, these warnings has reasons.

Check this topic, there are interesting parts about this question...

Regards,
Tamas

[esteveolm]

Yes, but I wan to know why it is required for this component and not required for others.

Is it because this component has @Scope(ScopeType.SESSION)?

Yes it is. If you run your app in a clustered environment, everything in Session context shuold be Serializable,

[ivan.tufegdzic]

OK I understand that.
But why Gavin's (and/or other Seam) classes not implement Serializable interface (Query, EntityHome,...) ?
These classes can be used as super class for our classes.