Please tell me more about your setup.
I think "/" is a "Rails" context, rails is working fine.
What URL would you like the servlets be?
You probably cannot use a WebApp Context to setup all servlets automatically for you if the Jave Web App uses "/" as well, it will conflict with the Rails Context. If it is the case, you have to define "Servlet" contexts one by one with corresponding servlet URI in the web.xml configuration.
I think jsp page should work fine, just make sure jsp files are available to lsws, copy those jsp files to the public folder of your rails application if needed.