Design enterprise applications with the EJB 3.0 Java Persistence API

Design enterprise applications with the EJB 3.0 Java Persistence API
http://www.ibm.com/developerworks/java/library/j-ejb3jpa.html

Here is a live example: (based on ibatis) http://www.jwebhosting.net/servlets/jpetstore5/index.html

Here is a Petstore 2.0 on google app engine: http://jazzmaster-examples.appspot.com/petstore/