Stateful session bean components are able to hold state not only across multiple invocations of the bean, but also across multiple requests. Application state that does not belong in the database should usually be held by stateful session beans. This is a major difference between Seam and many other web application frameworks. Instead of sticking information about the current conversation directly in the HttpSession, you should keep it in instance variables of a stateful session bean that is bound to the conversation context. This allows Seam to manage the lifecycle of this state for you, and ensure that there are no collisions between state relating to different concurrent conversations.
Stateful session beans are often used as JSF action listener, and as backing beans that provide properties to JSF components for display or form submission.
By default, stateful session beans are bound to the conversation context. They may never be bound to the page or stateless contexts.
Concurrent requests to session-scoped stateful session beans are always serialized by Seam.
