To enable remote debugging on your website edit the catalina.sh file on your tomcat installation. This file is located in the bin folder.

CATALINA_OPTS="-Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n"

Make sure port 8000 is open on your webserver, you should now be able to use the Netbeans remote debugger to attach to the tomcat server.