Can update data in a database and participate in transactions.
Either Stateful or Stateless.
Most complex component type in EJB model.
Operate as business objects and represent data in a database or a persistent data storage.
Each provides its own type of functionality and can enable the container to manage that functionality or manage by itself.
Beans that manage their own functionality are more complex but also have more options.
Session beans and entity beans use synchronous communication.
EJB executes client
requests and client waits for the EJB response.
