Exception loading sessions from persistent storage

I got this error. Please advise me how to overcome it.

Exception loading sessions from persistent storage

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.digitalyst.app.dtrack.Activity

at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1303)

at java.io.ObjectInputStream.readObject(ObjectInputStream.java:339)

at java.util.ArrayList.readObject(ArrayList.java:591)

[451 byte] By [hotbaboon] at [2007-11-26 10:18:58]
# 1
Hi ..If u r putting any object in sessionthey should implemented Serializalbe interface.
Roopesh_Kansara at 2007-7-7 2:15:52 > top of Java-index,Application & Integration Servers,Application Servers...