RMI server invocation delay

Question

Hello, I have a problem with server invocations. If I call the method that just prints to the console toString of passed MyClass instance, it takes 4.5 seconds.
If I pass String or null it works less than 10ms.
This problem appears only at the special environment.
Server should be at the Linux and client at the Windows.
The Client is an applet. This applet should be loaded from the Linux server.
But I have some Win computers that doesn't have this problem though they all are with XP and IE6.
Combinations like Linux-Linux, Windows-Linux, Windows-Windows work normal.
Besides if I even start this client from my IDE or just from my file system it works fast.
I can't even detect conditions which enough to reproduce this problem.
Here is my code:
TestServerIntf.java
public interface TestServerIntf extends Remote {
    void printMe(MyClass myClass) throws RemoteException;
}TestServer.java
public class TestServer implements TestServerIntf {
    public static void main(String[] args) {
        try {
            TestServerIntf engine = new TestServer();
            TestServerIntf stub =
                   (TestServerIntf) UnicastRemoteObject.exportObject(engine, 0);
            Registry registry = LocateRegistry.createRegistry(1099);
            registry.rebind("TestServer", stub);
            System.out.println("TestServer server bound");
        } catch (Exception e) {
            System.out.println("TestServer server exception:" + e.getMessage());
    public void printMe(MyClass myClass) throws RemoteException {
        System.out.println(myClass);
}TestClient.java
public class TestClient extends JApplet {
    private String host = "SERVER_HOST"; // specify here right host name
    private TestServerIntf server;
    public void init() {
        try {
            SwingUtilities.invokeAndWait(new Runnable() {
                public void run() {
                    createGUI();
        } catch (Exception e) {
            e.printStackTrace(); 
    private void createGUI() {
        try {
            Registry registry = LocateRegistry.getRegistry(host);
            server = (TestServerIntf) registry.lookup("TestServer");
        } catch (RemoteException e) {
             e.printStackTrace(); 
        } catch (NotBoundException e) {
             e.printStackTrace(); 
        final JLabel label = new JLabel();
        getContentPane().add(label, BorderLayout.CENTER);
        try {
            MyClass myClass = new MyClass();
            long t = System.currentTimeMillis();
            server.printMe(myClass);
            label.setText("PrintMe " + (System.currentTimeMillis() - t) + "ms!");
        } catch (RemoteException e1) {
             e1.printStackTrace(); 
}MyClass.java
public class MyClass implements Serializable {
}Besides if change the signature to "void printMe(Object object)" and pass "new MyClass[]{myClass}" than it takes 9 seconds! But "new MyClass[]{myClass1, myClass2}" takes also a 9 seconds.
I don't hope that you can reproduce this problem, but may be you have any ideas what is this problem connected with.
Please help.

Answer 1

Java does a reverse DNS lookup when you provide an IP address so DNS does come into it. I would say DNS is almost certainly the cause of the delay.