persistência

I am having the following problem: I can save / persist the two objects below, but the JPA is not binding the ID of Declaraca ... owing the objects already persisted in MySQL. Adicao: I really looked for everything personal, Could you give a strength ?

I am studying persistence for android, however I am having a hard time understanding the levels of persistence they do in app ... ther two if they are "the same function"? Can I share these preferences with each other? Does Web service fit a server type?

What Would that term be? I always see around and can not decipher!

What is JPA's "Optimistic Locking Field" and what is it for? I noticed that there is this option for Eclipse Link and Hibern ... m item) { this.item = item; this.id = item.getSKU(); } } Eclipse documentation link quoting is option