Impossible to inject database MailListener in an event listener

Listener are initialized at application startup (when the database is not ready and there is no XWikiContext available).

Problem is that DatabaseMailListener cannot be initialized then. It should probably be a bit lazier.

The workaround is to use

    @Inject
    @Named("database")
    private Provider<MailListener> databaseMailListenerProvider;

instead of the documented

    @Inject
    @Named("database")
    private MailListener databaseMailListener;