Problem with lost of the access to the RMI server

Question

Hi to all.
We have two applications. First one (master) provides to second (slave) through RMI service their data or other resources.
In the ordinary way all works fine. But if we need for some reason restart master application, slave can't access to the RMI service and calling of the method Naming.lookup(...) throws java.rmi.UnmarshalException: error unmarshalling return; nested exception is: java.io.EOFException
Interestingly, calling of method Namig.list(...) at this moment correctly returns an array of the names bound in the registry.
For completeness, in the time of restarting master application, classes of the RMI services are not changed and thus Stub/Skeleton classes are same on both sides.
What is reason for this behaviour? It is way to restart/restore RMI access of the slave application to the master without restarting server (Tomcat) of both applications?
Thank, Roman

Answer 1

Thank for your reply, but your suggestion not helped me now.
For registering and binding I used usual practices. Following snippets of code are inside method that perform initialization on application startup. I was trying three versions.
First version creates registry and binds service classes only. Without any checks.
try {
  LocateRegistry.createRegistry(rmiPort);
  String ip = Functions.getCurrentEnvironmentNetworkIp();
  if (ip.startsWith("?"))
    throw new Exception("Can't retrieve application IP address.");
  logger.info("Application IP address: " + ip);+
  RMIServiceCommonImpl rmiServiceCommon = new RMIServiceCommonImpl();
  String name = "rmi://" + ip + ":" + rmiPort + "/";
  Naming.rebind(name + IRMIServiceCommon.RMI_SERVICE_COMMON_NAME, rmiServiceCommon);
catch (Exception e) {
  logger.error("Failed to register RMI services: ", e);
}On first application start all is OK and client has no problem to access RMI service.
But if master application is restarted, calling of the method LocateRegistry.createRegistry(rmiPort); throws
java.rmi.server.ExportException: internal error: ObjID already in use
Since that, client can't access to the RMI service and following code (method Naming.lookup) throws
java.rmi.UnmarshalException: error unmarshalling return; nested exception is: java.io.EOFException
  String name = "rmi://" + ConfigServlet.getProperty("rmiHostUrl") + "/";
  IRMIServiceCommon service = (IRMIServiceCommon) Naming.lookup(name + IRMIServiceCommon.RMI_SERVICE_COMMON_NAME);Second version checks if registry exist and trying to get list of registered services. If services not exist Register is created.
try {
  Registry reg = LocateRegistry.getRegistry(rmiPort);
  String[] list = null;
  try {
    list = reg.list();
  catch (Exception ex) {
    // ignore
  if (list == null || list.length == 0)
    LocateRegistry.createRegistry(rmiPort);
  String ip = Functions.getCurrentEnvironmentNetworkIp();
  if (ip.startsWith("?"))
    throw new Exception("Can't retrieve application IP address.");
  logger.info("Application IP address: " + ip);
  String name = "rmi://" + ip + ":" + rmiPort + "/";
  RMIServiceCommonImpl rmiServiceCommon = new RMIServiceCommonImpl();
  Naming.rebind(name + IRMIServiceCommon.RMI_SERVICE_COMMON_NAME, rmiServiceCommon);
catch (Exception e) {
  logger.error("Failed to registering RMI services: ", e);
}Again, first start is OK.
In this case, after application restart, calling of method Naming.rebind() throws
java.lang.IllegalStateException at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1272)
INFO: Illegal access: this web application instance has been stopped already. Could not load eu.arachne.rmi.RMIServiceCommonImpl_Stub.
This exception is followed by similar exceptions, but differs in class names (stubs) - java.rmi.server.RemoteStub, java.rmi.server.RemoteObject, java.rmi.dgc.Lease, java.rmi.dgc.VMID, java.rmi.server.UID
Of course, client application can't access to the service.
The third version first unbinds all services and then performs binding again.
if (list == null || list.length == 0)
  LocateRegistry.createRegistry(rmiPort);
else {
  for (int ii = 0; ii < list.length; ii++)
    Naming.unbind(name + list[ii]);
}But again, rebinding fail as I mentioning above.
I don't know... :-( How I can solve this problem?
Thank, Roman