Exceptions occur while using POP3 protocol

[Mamata Chaudhari]

SEVERE: IOException while loading persisted sessions: java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.sun.mail.pop3.POP3Message

I am not getting why this exception has occurred.It throws the exception when i starts tomcat server.
I have used recieve() method in LoginAction which is used to recieved mails using POP3 protocol.
I am using JAVAMAIL 1.4

[David Newton]

This isn't really a Struts question.