To manually uninstall the jes service, use the adminstration console for your servlet container (e.g. the tomcat manager) to undeploy and delete the web application.
This will remove the web application, but will leave the working-directory intact. It is suggested that the working directory is then archived before being deleted by hand.
Alternately, run the installer application to automatically uninstall the jes service.
User's Guide
Installer's Guide
Developer's Guide