Yesterday Oracle released Oracle Application Server 10g (10.1.3.1) Developer Preview. The goal for this release to simplify development and deployment of service-oriented applications and hence it is termed as SOA Release. The SOA suite provides complete set of service infrastructure components such as Enterprise Service Bus, BPEL, BAM and Web Services Manager for creating, deploying and managing services, all available in a single install.
If you are an enterprise java developer and do not care about SOA, OracleAS 10.1.3.1 has something for you too. O It has complete support for EJB 3 and Java Persistence API and has annotations support in the Servlet container. OC4J 10.1.3.1 includes TopLink Essentials as the EJB3 JPA Provider.
You can download JDeveloper 10.1.3.1 and OC4J 10.1.3.1 standalone and to build and deploy EJB3/JPA applications.
See EJB3 Resources for updated howtos, samples, articles, etc.