Implementing an EJB 3.0 Stateful Session Bean

EJB 3.0 greatly simplifies the development of stateful session beans, removing many complex development tasks. For example:

• The bean class can be a plain old Java object (POJO); it does not need to implement javax.ejb.SessionBean.

• Home (javax.ejb.EJBHome and javax.ejb.EJBLocalHome ) and component (javax.ejb.EJBObject and javax.ejb.EJBLocalObject) business interfaces are not required.

  If you choose to use a remote component interface, you can use a plain old Java interface (POJI); it does not need to extend javax.ejb.EJBObject.

• Annotations are used for many features.

• A SessionContext is not required: you can simply use this to resolve a session bean to itself.

For more information, see "What is a Stateful Session Bean?".

To implement an EJB 3.0 stateful session bean:

1. Optionally, create one or more remote component interfaces and/or local interfaces for your stateless session bean.

   You can create a plain old Java interface (POJI) and define it as a remote interface with the @Remote annotation or as a local interface using the @Local annotation.

   You can specify multiple interfaces using the annotation's value attribute:

   @Stateless
   @Local (value={Local1.class})
   @Remote (value={Remote1.class, Remote2.class})
   
   

2. Create the stateful session bean class.

   You can create a plain old Java object (POJO) and define it as a stateful session bean with the @Stateful annotation.

   Extend your remote interface, if used.

3. Implement your business methods.

   To define a method of your stateful session bean class as a remove method using the @Remove annotation.

4. Optionally, define lifecycle callback methods using the appropriate annotations.

   You do not need to define lifecycle methods: OC4J provides an implementation for all such methods. Define a method of your stateful session bean class as a lifecycle callback method only if you want to take some action of your own at a particular point in the stateful session bean's lifecycle.

   For more information, see "Configuring a Lifecycle Callback Method for an EJB 3.0 Session Bean".

5. Complete the configuration of your session bean (see "Using EJB 3.0 Session Bean API").