Seam components are POJOs (Plain Old Java Objects). In particular, they are JavaBeans or EJB 3.0 enterprise beans. While Seam does not require that components be EJBs and can even be used without an EJB 3.0 compliant container, Seam was designed with EJB 3.0 in mind and includes deep integration with EJB 3.0. Seam supports the following
EJB 3.0 stateless session beans
EJB 3.0 stateful session beans
EJB 3.0 entity beans
EJB 3.0 message-driven beans
Stateless session bean components are not able to hold state across multiple invocations. Therefore, they usually work by operating upon the state of other components in the various Seam contexts. They may be used as JSF action listeners, but cannot provide properties to JSF components for display.
Stateless session beans always live in the stateless context.
Stateless session beans are the least interesting kind of Seam component.