http://www.javacodegeeks.com/2010/05/gwt-2-spring-3-jpa-2-hibernate-35.html

This step by step guide will present how to develop a simple web application using Google's Web Toolkit (GWT) for the rich client and Spring as the back – end, server side framework. The sample web application will provide functionality to make CRUD (Create Retrieve Update Delete) operations to a database. For the data access layer we will use JPA over Hibernate and for a database we will use Hypersonic. Of course you can change the configuration and use whatever you like. We will deploy the web application to an Apache – Tomcat instance.