Hi,
Are you starting Jetty from eclipse or as a standalone?
If you’re starting it from inside eclipse, then just follow the tutorial I sent before.
If you’re starting Jetty as standalone, then you need to add the javaagent argument to the Jetty startup like shown here: http://manuals.zeroturnaround.com/jrebel/standalone/launch-from-command-line.html#jetty-5-x-6-x-7-x-8-x-and-9-x
You also need to add rebel.xml files to your project. You can do it automatically in eclipse by enabling JRebel Nature: http://manuals.zeroturnaround.com/jrebel/ide/eclipse.html#project-configuration
Alternatively you can create the rebel.xml file manually: http://manuals.zeroturnaround.com/jrebel/standalone/config.html
Please let us know if you need any more help with setting up JRebel.