Google App Engine and Java Persistence API and Java Data Objects

• JAP (Java Persistence API) and JDO (Java Data Objects) can be used in Google App Engine Web Apps to access the GAE datastore.
• JAP and JDO implementations in GAE are built on top of low-level API for App Engine datastore   

GAE datastore Concept	JAP Concept
Kind	Class
Object	Entity
Properties	Fields

There are some concepts that are specific only to App Engine and do not have equivalents in JAP

 

You can also use the low-level API that is GAE specific

• com.google.appengin.api.datastore.* package
• sometimes this is a necessity to use (as JAP,JDO do not have same functionality)
• however if you can use JAP or JDO, do so as then your webapp will be more portable (moving to a not GAE web app environment)

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