CDI EJB

gistfile1.txt

CDI scopes
javax.enterprise.context.@RequestScoped
javax.enterprise.context.@SessionScoped
javax.enterprise.context.@ApplicationScoped
javax.enterprise.context.@ConversationScoped -  If the user is doing multiple things at the same time, there are multiple conversations.
javax.enterprise.context.@Dependent - default scope. An instance of a dependent bean is never shared between different clients or different injection points. It is strictly a dependent object of some other object. They don't use proxy objects.
javax.inject.@Singleton - don’t have a proxy object. Clients hold a direct reference to its instance. Problems with serialization it's better to add @ApplicationScoped allowing the container to proxy the bean
@SessionScoped or @ConversationScoped must be serializable

Qualifiers
javax.enterprise.inject.@New - The built-in qualifier @New allows us to obtain a dependent object of a specified class. Even if the class is already declaren with different scope

Type safe dependency injection
javax.inject.@Inject - 


javax.inject.@Qualifier - we need to implement this annotation
javax.enterprise.inject.@Alternative - by default is disabled, With this annotation we can solve ambiguous dependencies eg. by annotationg on possible bean.
javax.enterprise.inject.@Any Instance<HelloBean> beans - qualifier can be used when we have multiple implementations of one interface and we want to inject them all in another bean