Description: When OptimisticSerialization is turned on, WebLogic server does not serialize-deserialize context and request attributes upon getAttribute(name) when a request gets dispatched across servlet contexts. This means you will need to make sure that the attributes common to Web applications are scoped to a common parent classloader (they are application-scoped) or placed in the system classpath if the two Web applications do not belong to the same application. When OptimisticSerialization is turned off (which is the default) WebLogic Server does serialize-deserialize context and request attributes upon getAttribute(name) to avoid the possibility of ClassCastExceptions. The value of OptimisticSerialization can also be overridden for specific Web applications by setting the optimistic-serialization value in weblogic.xml.