jsf - Session map is null when printed -

i working on jsf1.1 jsp presentation technology. have managed bean arraylist , display list in rows. works fine. have session replication 2 server nodes , when replicate session, , put 1 of cluster down, app on second cluster session attributes lost.

i tried print sessionmap using externalcontext see session attributes null too.

what possible reason?

the attributes not serializable. that's requirement them persist on disk and/or transfer bytes on network.

to fix this, ensure session attributes (including session scoped managed beans) implement serializable this:

public class somesessionclass implements serializable {     // ... } 

don't forget make members serializable whenever applicable. e.g.

public class somesessionclass implements serializable {     private somenestedclass foo; // has implement serializable well!     // ... }