Apache Camel

Introduction:
http://stackoverflow.com/a/11540451/2293534
Short Example:

1. http://thilina.piyasundara.org/2010/12/lets-ride-camel-simplest-program-to.html

Best Example:

1. http://www.mastertheintegration.com/camel/camel-introduction/camel-helloworld.html - very good

Others:

1. http://onjavahell.blogspot.com/2009/05/taking-apache-camel-for-ride.html