Can Hibernate 3.5.x be used as the JPA provider instead of the default provider in the latest version of Google App Engine (1.3.2)
No, Hibernate can't be used with Google App Engine. Please see Will it play with App Engine.
You cannot currently use Hibernate directly. The differences between the App Engine datastore and SQL were too great to get the standard Hibernate up and running under App Engine. App Engine does support JDO and JPA, so you may be able to convert your Hibernate code to use one of these ORM interfaces.