Using a singleton service

Java EE provides singletons through the use of the @Singleton annotation. In practice, this annotation will guarantee that your class will be loaded only once per JVM or per application server instance. Although this is a powerful feature, if your business scenario can't cope with this behavior (duplicate component instances, one per JVM), you need another approach; the singleton service offered by WebLogic can offer an elegant solution for such cases. This feature guarantees that a given singleton class will have only one instance across a cluster, automatically managing failover and migration to another server instance in case of failure.

In the singleton ReservationCodeBean class there is a functionality that generates control numbers used to identify the reservations. The actual implementation is perfectly fine for a single server application, but running this application on multiple servers will end up creating several instances of ReservationCodeBean, one per...