Question

My application needs some meta data configuration to be loaded at server start up. Meta data are annotations and its do-it-once-forget it-and-use kind. So reading annotations and loading the MetaData objects involves lot of reflection hence I want to do it only once.

Is there any way other than using using Singletons ? I saw @Singleton EJBs which may serve the purpose. But I’m using EJB 3.0 hence that support is not available.

Do you see any other approach (efficient and simple) I can use for this purpose ?

To be more clear :

Using annotations on some classes we are building some configuration objects, that’ll be used throughout the application. Hence reading the annotations and building the config objects has to be done only once.

Answer 1

I have found solution for the problem.

I have a @PostConstruct annotated method which reads all the configuration meta data and create the objects. And in the EJB deployment descriptor I configure the initial-number of beans in pool as 1 and also maximum number of beans as 1. Hence this would be a singleton and at the same time would be loaded on server startup.