EXP 6: java.lang.IllegalArgumentException: setAttribute: Non-serializable attribute with name

Prolem
Server log show error:
java.lang.IllegalArgumentException: setAttribute: Non-serializable attribute with name sessionBean

Cause
The instance "sessionBean" of SessionBean class is non--serializable when enable distribute feature on web.xml

Solution
Implement Serializable to SessionBean class  or super of SessionBean class