Geomajas is the extensible open source framework for building web GIS applications, enabling integrated GIS solutions for businesses and government.
It has an integrated client-server architecture, with a high focus on server-side integration of your data (be it through GeoTools or Hibernate).
This means that you apply your security and business logic on the server before anything gets send to the client, resulting in robust applications and a real thin client.
These details are provided for information only. No information here is legal advice and should not be used as such.