At work I use a third party vendor implementation of apache and tomcat from a company named Covalent. I installed this locally in order to have a sandbox to play in and I wanted to set up JMX on the tomcat instance in order to play with Groovy, Glassbox, and some other useful open-source tools.
Setting up JMX when it isn't already set up for you can be a real headache. Setting up JMX in tomcat on Windows can be a really big headache. This may apply to regular tomcat but I haven't tested it yet--it was definitely applicable to the covalent-implementation.
If you have the tomcat instance installed as a service, any JAVA_OPTS updates that are made won't take affect unless you delete the service and recreate it. I spent hours trying to get this working on my new Vista machine. Everything looked right but the RMI port still would not bind. Finally, out of frustration, I deleted the service and re-created it and everything worked.
I'd like to know if this is Vista specific or if it happens across other Windows versions so if any one reading this could comment on Win2k or if this is the case with regular apache, it would be a good tip for the knowledge base.