By now I am sure everyone has heard that Google App Engine has supported Java and this is totally exciting for Java developers including myself. Not only Java is supported, but one can use JPA to store/retrieve data from Google DataStore. The current support has pretty much most of what one needs to build a useful Java web based application running on Google App Engine.
The next thing we need is some MVC framework for the presentation tier. Surprisingly, there is a lot of folks trying to use Spring MVC and Spring framework. This seems to make sense because Spring Framework provides both web-tier support and back-send support like JPA integration and transaction management. Maybe that’s why I haven’t seen many folks using Struts or JSF with Google App Engine.
There is a lot of buzz on google-appengine-java-group forum. Folks are trying out different technologies and exchanging tips and tricks.
As for myself, I ported the JDO Guestbook example to use Spring MVC + JPA and it is working just fine. Check it out when you get a chance.
From what I have been seeing, the following technologies are working on GAE:
Spring MVC, Tile 2.0.7.
One of the most frustrating things that most folks encountered is that their GAE applications work on their local box and it doesn’t work when running on GAE production. Most of the time it is related to security issue. GAE allows a subset of JRE classes and their white list is on their site.
I have an application in mind and I will be busy in the next several weeks developing it. Stay tune.