eXo WCM is a fully integrated Content Management solution inside GateIn.
Basically, we're using the extension mechanism inside GateIn to add content features. If you want more infomation about the extension mechanism, you can read the GateIn documentation :
[http://docs.jboss.com/gatein/portal/3.1.0-FINAL/reference-guide/en-US/html/index.html]

This integrated solution provides users with a comprehensive platform for integrating applications and managing and publishing content - all from a single, familiar console.

When starting a new project, you can see eXo WCM as a WCM Java developer Platform. In this reference guide, we will give you guidelines so you can build stable applications using eXo WCM from the inside.
