Spring-portlet-sample is a project mainly written in Java, it's free.
Sample code for a Spring Portlet MVC app, complete with an integration test class for a controller
Code for blog on integration testing for portlet MVC: http://jamesfarrell129.wordpress.com/2011/04/20/integration-testing-for-spring-portlet-mvc/
Project can be built using Maven pom. Based on a sample application found here: http://code.google.com/p/spring-portlet-sample/source/browse/