Containers and WebApplications

from here:
NanoWar works by having a hierarchy of containers, one at the application scope, one in each session whose parent is the application container, and one is created for each request with the parent as the appropriate session container.
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This model allows for stateful components in the meaningful scopes -- if you have session state, it is stored in a component scoped to the session. Actions can be stored at any level -- stateless ones (a la Struts or SpringMVC) may be defined in the application level scope, one-off actions (a la WebWork) can be defined in the request scope container. Wizard style ones (if you don't have a concept of wizard scope) can be session scoped, and use a state machine to figure out what is next.