anchor.diff:  }
   ----
   
  +Alternatively, immutable classes can be enumerated via the distributable-web deployment descriptor.
  +
  +e.g.
  +[source,xml]
  +----
  +<distributable-web xmlns="urn:jboss:distributable-web:1.0">
  +    <session-management>
  +        <immutable-class>foo.bar.ImmutableClass</immutable-class>
  +        <immutable-class>...</immutable-class>
  +    </session-management>
  +</distributable-web>
  +----
  +
   [[session_attribute_marshalling]]
   === Session attribute marshalling
   
  
positive.code: 
  A web application can override the default distributable session management behavior in 1 of 2 ways:
  
  1. Reference a session-management profile by name
  1. Provide deployment-specific session management configuration
  
  === Referencing an existing session management profile
  
  
negative.code: An externalizer is an implementation of the `org.wildfly.clustering.marshalling.Externalizer` interface, which dictates how a given class should be marshalled.
  An externalizer reads/writes the state of an object directly from/to an input/output stream, but also:
  
  . Allows an application to store an object in the session that does not implement `java.io.Serializable`
  . Eliminates the need to serialize the class descriptor of an object along with its state
  
  e.g.
  [source,java]
  