In a real OOAD, our design is first to do UML build, and finally put a system to all objects (this thing is not so simple) use class diagrams to reflect a complete design, we will finally get these kinds : Control the class of business logic, save business data class module (bean class), auxiliary class or more (specific analysis of specific issues, but the data required to be intertroveted to a class MODULE is more suitable for layers).
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Hibernate deep adventure
