thanks! that's extremely helpful to know...
interestingly though, when I start up a SIGAR shell and issue the command directly, I get:
sigar> ps State.Name.eq=java,Args.*.ct=catalina.home
8241 tomcat Jul11 2.3G 2.1G 20M S 12:0 java:org.apache.catalina.startup.Bootstrap
9254 tomcat Jul11 2.4G 340M 20M S 3:20 java:org.apache.catalina.startup.Bootstrap
sigar>
in other words, it does indeed seem to show me the 2 active tomcat instances running on that server.
Why then does the availability metric show that Tomcat is down?
As you suggest, there are other better metrics to use for alerting purposes, but I just find this 0% availability thing irksome to look at on the web GUI when I know it's wrong.