title: How to Multi-threading this example of code?
body: <p>I would like to simulate a distributed system and how machines do their works, the topology adopted is a centralized one, I have many little systems in which each sub systems adopts this topology, I mean I suppose that my distributed system constitutes of many centralized systems.
  I have created a simple discrete event simulator, which simulates the work in side One centralized system, the code is like:    </p>
  
  <pre><code>public class SimuleOnesystem { 
  // a set of parameters
  class Arrival{// here we simulate the arrival of works to a server
   // the code..
  }
  class Service{// here we simulate the services  }
  class Departure{// means that the work is well done
   }
  }
  </code></pre>
  
  <p>My question is, how could I multithreaded this code, I mean I  would like to execute for example 5 Centralized systems at the same time in which each system has its own simulation clock, eventList and so on, and these systems can communicate between each other in term of sending and receiving request and executing jobs etc...</p>
  
  <p>Thanks in advance.</p>