Sunday, June 1, 2014

EJB 3.1 Component Types

EJB 3.1 component types are:

  1. Session Beans
    1. Stateless Session Beans (SLSB)
    2. Stateful Session Beans (SFSB)
    3. Singleton Session Beans
  2. Message Driven Beans (MDB's)
  3. Entity Beans

  • The Stateless Session Bean does not preserve conversational state.
  • The Stateful Session Bean preserves conversational state and there is one instance of the session bean per client.
  • The Singleton Session Bean is new to the EJB 3.1 Specification. There is only one instance of this bean type.
  • The Message Driven Bean acts as an event listener. It cannot be called from the client.

For each Bean, there are lifecycle callbacks that must follow the pattern void <METHOD>().

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