Best Design for a Facebook clone on GAE Java

Question

My current App is written in Python on GAE which can do Contacts management, Genealogy, Social Networking, Photo sharing, Telecom Integration (SMS, iVRS, URL Billing), CRON and performs business logic operations for our Mobile Apps. Current Architecture indlues python, django, jquery, memcache and few telecom APIs.

Now, It feels that an SOA Architecture on GAE using Java would be really ideal and scalable for this kind of App where we want to build new features like widgets that users can turn on or off and third party developers can also develop and deploy features.

Please correct me or improve the following design decision:

1. UI (Current plan is GWT)
2. Sessions, Security and ACL (Spring MVC 2.x)
3. Reusable Business Logic components (?)
4. Implementation of Web Services (?)

Your advice would really help.

Answer 1

This question is quite broad, and it's going to be difficult for anyone to give you a non-speculative answer, but I feel like I should mention that I have seen a number of question here on SO regarding gae-java applications that use large components liek Spring having start-up times that are so long that the application gets into quota and timeout problems.

Before you go down this road, take your time to do some careful research into other people's successes and failures with using large, 3rd-party components as part of their applications.