We are trying to deploy 2 versions of the same application on Tomcat 7 to test its parallel deployment features for our application.
Not meeting with success, I was looking for a definitive guide for parallel deployment on Tomcat 7.
Our application is a JSP based application but we can have changes often.
The definitive reference for parallel deployment comes directly from the Apache Software Foundation: http://tomcat.apache.org/tomcat-7.0-doc/config/context.html#Parallel_deployment.
Additionally, Mark Thomas wrote a summary article explaining how this feature works on the Context Container and across clusters: http://www.tomcatexpert.com/blog/2011/05/31/parallel-deployment-tomcat-7.