I suppose it depends on what kind of monitoring  you are thinking about.
The technologies you have listed are really all tools to do a job, and
may or may not be useful to you.

You need to have a full understanding of the features that you intend to
develop and then work out what technology that can best service those
features as quickly and as efficiently as possible.

Features that you should consider are:

Who is going to use the monitoring system.
What exactly you are monitoring
What kind of UI do they want to use.
When is this information needing to be displayed.
How can you access that information.

They are really broad subjects too, don't just think that "network
traffic" would be a sufficient answer to what you are monitoring. You
need to know exactly what you are trying to accomplish before you just
start hacking at code.

I don't think anybody here can say "You need to use RMI!!!" at this
point because nobody here really has any idea what you want to create
(other than a very broad idea of a monitoring system).