The Lifecycle of a Singleton Session Bean

Like a stateless session bean, a singleton session bean is never passivated and has only two stages, nonexistent and ready for the invocation of business methods, as shown in Figure 14–5.

Figure 14–5 Lifecycle of a Singleton Session Bean

The EJB container initiates the singleton session bean lifecycle by creating the singleton instance. This occurs upon application deployment if the singleton is annotated with the @Startup annotation The container performs any dependency injection and then invokes the method annotated @PostConstruct, if it exists. The singleton session bean is now ready to have its business methods invoked by the client.

At the end of the lifecycle, the EJB container calls the method annotated @PreDestroy, if it exists. The singleton session bean is now ready for garbage collection.