Quote from Doc "The --inPlace option allows you point to and deploy an application directly from a directory external to Geornimo without the need for even packaging the application."

So the jar should be unpacked and in its full-blown structure. In this way, you can update the classes within it without redeploying.

After the directory is deployed, insert the dependency in the deployment plan of your WAR. 

Hope this answers your question.

Jeff C