I've had an issue with my JSS's Tomcat 7 installation going unresponsive over the past couple of weeks. To (hopefully) fix it, I've upped my Tomcat memory allocation and set up a monitoring script to check Tomcat and restart it if it stops running.
I've posted the information about the monitoring scripts here:
http://derflounder.wordpress.com/2011/12/14/monitoring-the-casper-jss-tomcat-on-red-hat-linux/