That's a pretty vague requirement. Let's skip over the obvious questions like what does "display" mean and just talk about generalities, then.
As you know, RMI stands for "Remote Method Invocation". So that would mean you would write a class containing a method which displays the message, whatever that might involve, and then you would invoke it remotely. Just like you would invoke any other RMI method.
Does that help? Or do you actually have a question like "How do I invoke an RMI method?" or "How do I display a message on a server?"
subject: How can i display a message at the Server using Java RMI