Suppose you have the JMX Server (alias 'JMX Agent' alias 'the JVM you want to connect to') running on 'TARGET MACHINE' with the RMI registry port at 'RMI REGISTRY PORT' and the JMX RMI server port at 'JMX RMI SERVER PORT'.
Note:
The RMI registry tells JMX clients where to find the JMX RMI server port; information can be obtained under key jmxrmi.
The RMI registry port is generally known as it is set through system properties at JVM startup.
The JMX RMI server port is generally not known as the JVM chooses it at random (if no other precautions are taken).
The following URI will lead to successful connection (tested)
Yes, that works! The JMX RMI server port is nicely obtained from the registry. On second thoughts, the target machine should also be obtained from the registry, thus:
service:jmx:rmi://192.168.30.10:1234 - says that there is a JMX Agent on the machine with IP address 192.168.30.10. The JMX agent is using (TCP) port 1234 to provide JMX service(s) over RMI (basically acts as an RMI server).
/jndi/rmi://192.168.30.10:2344/jmxrmi - says that the RMI stub to interact with the JMX Agent over RMI can be found in the RMI registry which is running on the machine with IP address 192.168.30.10 and is using (TCP) port 2344. To get the RMI stub you need to lookup the "jmxrmi" binding.
Previous answers suggest that the 2nd part of the URL is to obtain the server port of the JMX RMI server. That is not correct. The JMX RMI server port is (TCP) 1234 and is part of the URL. What you get from the RMI registry is the RMI stub (javax.management.remote.rmi.RMIServerImpl_Stub) which you can use to talk to JMX Agent (MBean Server) over RMI.