This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
My application needs to access different external systems(LDAP, webservices, email etc.). I think DAO is the perfect choice here. To provide a unified DAO layer, I decided to use DAO to access all external systems including webservices(I don't want to use dependency injection as i don't want to mix my business layer with external system).
However I google for a long time, can't find a good reason or article talking about using DAO to access web services.