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 POJO; it does not need to implement javax.ejb.SessionBean.

• The business interface is optional.

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

  The EJB 3.0 local or remote client of a session bean written to the EJB 3.0 API accesses a session bean through its business interface. The business interface of an EJB 3.0 session bean is an ordinary Java interface, regardless of whether or not local or remote access is provided for the bean.

• 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 the following:

• "What is a Stateless Session Bean?"

• "Adapting an EJB 3.0 Stateful Session Bean for an EJB 2.1 Client"

Note:

You can download an EJB 3.0 stateful session bean code example from: http://www.oracle.com/technology/tech/java/oc4j/10131/how_to/how-to-ejb30-stateful-ejb/doc/how-to-ejb30-stateful-ejb.html.

To implement an EJB 3.0 stateful session bean, do the following:

1. Create the stateful session bean class.

   You can create a POJO and define it as a stateful session bean with the @Stateful annotation.

   Note:

   OC4J ignores the @Stateful attribute mappedName.

2. Implement your business methods.

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

3. Optionally, define life cycle callback methods using the appropriate annotations.

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

   For more information, see "Configuring a Life Cycle Callback Interceptor Method on an EJB 3.0 Session Bean".

4. Optionally, define OC4J-proprietary deployment options.

   In an EJB 3.0 application, you can do this by annotating your stateful session bean class with the OC4J-proprietary oracle.j2ee.ejb.@StatefulDeployment annotation (see "Configuring OC4J-Proprietary Deployment Options on an EJB 3.0 Session Bean").

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