JPA : Many to many relationship in Google App

I'm beginner of Google app. I want to know how to code many to many relationship for JPA in Google app. Could u giv开发者_运维百科e me the example? I'm trying to connect Order, Order_Item and Product.

GAE has a complete walkthrough of using JPA in GAE. You should hardly need to come here asking for someone to write the code for you.