Just upgraded from Zabbix 1.8 to 2.0 and was pleased to find that Java support has finally been added! However, the Java Gateway is currently hard-coded to access JMX over RMI, which is awful for firewalls and tunneling, and requires you to open up your entire RMI registry to the outside world, which isn't the most secure thing to do. I set up a JMXMP agent on my server, and patched Zabbix's Java Gateway to speak JMXMP, which is newer and better way to do remote JMX monitoring. In my patched version, I've simply replaced the RMI implementation with the JMX implementation, but a more flexible way of implementing this might be to have the Zabbix GUI let the user input the entire JMX URL.