Name: rlT66838 Date: 11/12/99


When LocateRegistry.getRegistry(portnumber) is attempted on a port with a tcp server it does not throw an exception. Subsequent calls to Registry.list, Naming.rebind(portnumber) or Naming.lookup(portnumber) hang and never return.

The RMI server:
package test;
import java.lang.*;
import java.io.*;
import java.util.*;
import java.net.*;
import java.rmi.*;
import java.rmi.registry.*;
import java.rmi.server.*;


public class SrvApp
{
public static int m_nRMIport = 4013;
public static InetAddress m_SrvAddr = null;
public static String m_strSrvAddr = new String();

    private static Registry m_reg = null;
    private static boolean m_bServerInRMI = false;

public SrvApp() {}

public static void getSrvAddress()
{
try
{
m_SrvAddr = InetAddress.getLocalHost();
}
catch (Exception exc)
{
System.out.println("SrvApp.getSrvAddress Error: " + exc);
System.out.println("Unable to obtain Local Host InetAddress.");
System.out.println("RMI lookups to connect to the Server may not work properly.");
}
}

public static void createConnectionName()
{
StringBuffer strbSrvAddr = new StringBuffer();
if (m_SrvAddr != null)
{
strbSrvAddr.append("rmi://");
strbSrvAddr.append(m_SrvAddr.getHostAddress());
strbSrvAddr.append(":");
strbSrvAddr.append(m_nRMIport);
strbSrvAddr.append("/");
}
strbSrvAddr.append("Server");
m_strSrvAddr = strbSrvAddr.toString();
}

public static void main(String args[])
{
getSrvAddress();

createConnectionName();

        // get or set the SecurityManager.
try
{
if (System.getSecurityManager() == null)
                System.setSecurityManager(new RMISecurityManager());
        }
        catch (Exception ex)
        {
            System.out.println("SrvApp Error setting Security Manager: " + ex);
        }

        // create or get the rmiregistry.
        try
        {
            m_reg = LocateRegistry.createRegistry(m_nRMIport);
        }
        catch (Exception excp)
        {
            //System.out.println("SrvApp.main Exception creating the rmiregistry: " + excp);
excp.printStackTrace();
            System.out.println("Trying to use the existing rmiregistry.");
            try
            {
System.out.println("Attempting LocateRegistry.getRegistry.");
                m_reg = LocateRegistry.getRegistry(m_nRMIport);
System.out.println("Passed LocateRegistry.getRegistry.");
            }
            catch (Exception excptn)
            {
                System.out.println("SrvApp.main Exception trying to use the existing rmiregistry: " + excptn);
System.out.println("Unable to get or create an rmiregistry.");
System.out.println("The Server cannot run without a functional RMI.");
System.out.println("Exiting.");
System.out.flush();
System.exit(0);
            }
        }

        // If you have not exited from an RMI error get the rmiregistry's list.
        /*try // try to find the log_server entry.
        {
System.out.println("Attempting Registry.list.");
            String[] strList = m_reg.list();
System.out.println("Passed Registry.list.");
            System.out.println("The RMI list: ");
            for (int j = 0; j < strList.length; ++j)
            {
                String strTemp = strList[j];
                System.out.println(strTemp);
            }
        }
        catch (Exception excn)
        {
            System.out.println("SrvApp getting rmiregistry list Error: " + excn);
        }*/

        for (int i = 0; i < 5; i++)
        {
try
{
System.out.println("RMI name is: " + m_strSrvAddr);
SrvInterfaceImpl w = new SrvInterfaceImpl();
System.out.println("Attempting Naming.rebind in SrvApp.main.");
Naming.rebind(m_strSrvAddr, w);
System.out.println("Passed Naming.rebind in SrvApp.main.");
i = 5;
}
catch(Exception e)
{
System.out.println("SrvApp RMI Error: " + e);
if (i == 4)
{
System.out.println("Unable to connect to RMI.");
System.out.println("The Server cannot run without a functional RMI.");
System.out.println("Exiting.");
System.exit(0);
}
}
}
}

}
The Interface:
package test;
import java.lang.*;
import java.rmi.Remote;
import java.rmi.RemoteException;

public interface SrvInterface extends Remote
{
public void hello() throws RemoteException;
public boolean isAlive() throws RemoteException;

}
The Interface implementation:
package test;
import java.lang.*;
import java.io.*;
import java.rmi.*;
import java.rmi.server.*;

public class SrvInterfaceImpl extends UnicastRemoteObject implements SrvInterface
{
public SrvInterfaceImpl() throws RemoteException
{
}

public void hello() throws RemoteException
{
System.out.println("Hello");
}

public synchronized boolean isAlive( ) throws RemoteException {return true;}
}
The Server Client:
package test;
import java.util.*;
import java.lang.*;
import java.net.*;
import java.rmi.*;
import java.rmi.server.*;
import java.rmi.registry.*;


public class SrvClient
{
    private static SrvInterface srvInterface;
    private static boolean m_bConnectedToSrv = false;
public static InetAddress m_SrvAddr = null;
public static String m_strSrvAddr = new String();
public static int m_nRMIport = 4013;

public SrvClient()
{
getSrvAddress();
createConnectionName();
m_bConnectedToSrv = connectRMI();
}

    public static void setSecMngr()
    {
try
{
if (System.getSecurityManager() == null)
                System.setSecurityManager(new RMISecurityManager());
        }
        catch (Exception ex)
        {
            System.out.println("SrvClient Error setting Security Manager: " + ex);
        }
    }

public static void getSrvAddress()
{
try
{
m_SrvAddr = InetAddress.getLocalHost();
}
catch (Exception exc)
{
System.out.println("SrvClient.getSrvAddress Error: " + exc);
System.out.println("Unable to obtain Local Host InetAddress.");
}
}

public static void createConnectionName()
{
StringBuffer strbSrvAddr = new StringBuffer();
if (m_SrvAddr != null)
{
strbSrvAddr.append("rmi://");
strbSrvAddr.append(m_SrvAddr.getHostAddress());
strbSrvAddr.append(":");
strbSrvAddr.append(m_nRMIport);
strbSrvAddr.append("/");
}
strbSrvAddr.append("Server");
m_strSrvAddr = strbSrvAddr.toString();
}

public static boolean connectRMI()
{
setSecMngr();

        for (int i = 0; i < 5; i++)
        {
try
{
if ( i == 0) System.out.println("SrvClient's RMI name is: " + m_strSrvAddr);
System.out.println("Attempting Naming.lookup in SrvClient.connectRMI.");
srvInterface = (SrvInterface)Naming.lookup(m_strSrvAddr);
System.out.println("Passed Naming.lookup in SrvClient.connectRMI.");
i = 5;
}
catch( Exception e )
{
//System.out.println("NewTestClient Error: Can't connect to Test Server. " + e);
if (i == 4)
{
System.out.println("NewTestClient could not connect to a Test Server.");
     return false;
}
}
}
try
{
boolean brtval = isAlive();
return brtval;
}
catch (Exception eee)
{
//System.out.println("SrvClient.isAlive Error: " + eee);
return false;
}
//return true;
}

    public static boolean isAlive()
        throws RemoteException
    {
        try
        {
            return srvInterface.isAlive();
        }
        catch (java.rmi.RemoteException eee)
        {
            throw eee;
        }
    }

public static boolean isConnectedToServer()
{
return m_bConnectedToSrv;
}

}
The Port Blocker:
package test;

import java.io.*;
import java.net.*;
import java.util.*;

public class PortBlocker
{
public static DatagramSocket socket = null;
public static int nWhatPort = -1;
public static InetAddress srvClntIPAddr = null;

public PortBlocker() {}

public static void SocketConnect()
{
try
{
ServerSocket s = new ServerSocket(4013);
for ( ; ; )
{

System.out.println( "PortBlocker waits for accept " );
try
{
Socket incoming = s.accept();
System.out.println( "PortBlocker accept ");
char[] szReceive = new char[1024];
BufferedReader in = new BufferedReader(new InputStreamReader(incoming.getInputStream()));

in.read(szReceive,0,1024);
String strTemp = new String(szReceive);
strTemp.trim();
System.out.println(strTemp);
while (!strTemp.equals("QUIT!"))
{
in.read(szReceive,0,1024);
strTemp = new String(szReceive);
strTemp.trim();
System.out.println(strTemp);
}
DataOutputStream out = new DataOutputStream (incoming.getOutputStream());
in.close();
out.writeBytes("Goodbye");
out.flush();
out.close();
incoming.close();
}
catch (Exception excptn)
{
System.out.println("PortBlocker.SocketConnect Error: " + excptn);
String strlogmessage = new String("Error in PortBlocker's TCP socket accept: ");
}
} // for
}
catch (Exception e )
{
System.out.println("PortBlocker.SocketConnect Error: " + e);
String strlogmessage = new String("Error setting up PortBlocker's TCP socket connection: ");
}
}

public static void main(String args[])
{
SocketConnect();
}
}
Run the PortBlocker first. Then start up the SrvApp.
The Naming.rebind hangs in SrvApp. By uncommenting out the reg.list portion, you can get that to hang.
(Review ID: 96167)
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