@Override
  public Object execute(Object obj) {
    List<Object> params = (List<Object>) obj;

    // param 0: groupId
    groupId = ((String) params.get(0));

    // param 1: to indicate if all Servers will run in a single computer
    // or they will run Servers hosted in different computers (or more than one
    // Server in a single computer but this computer having the same internal and external IP
    // address)
    // * true: all Server run in a single computer
    // * false: Servers running in different computers (or more than one Server in a single computer
    // but
    // 			this computer having the same internal and external IP address)
    SimulationData.getInstance().setLocalExecution(((String) params.get(1)).equals("localMode"));

    try {
      users = (List<String>) params.get(2);
      operations = (List<Operation>) Serializer.deserialize((byte[]) params.get(3));
    } catch (ClassNotFoundException | IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }

    return null;
  }