I have a method on an RMI server, and this method changes a state variable.

I don't want multiple RMI clients to modify this variable concurrently (i.e.
by calling the method on their stub).

Should I make the method synchronized? Is this class thread-safe?

The class is shown below.

public class RMIServer extends UnicastRemoteObject
 implements ServerInterface {
 private int state = 0;
 RMIServer() throws Exception {
   super();
   String rmiObjectName =
   "rmi://"+ InetAddress.getLocalHost() + "/RMIServer";
   Naming.rebind(rmiObjectName, this);
 }

 public void update_state(int increment){
   state = state + increment;
 }
}