Name: rm29839 Date: 05/28/98


I have created an example that illustrates the problem
in the following classes. Basically, I created an RMI
server that starts and registers a UnicastRemoteObject.
The Object throws a NullPointerException exception when
any of the methods are called. Next I created a client
which binds to the RemoteObject and calls one of the
methods. Naturally a RemoteException with a nested
NullPointerException is thrown, however, the stack trace
on the RemoteException does not report the client code
line that the exception was generated from. If I try
to fill in the stack trace on the client I get an invalid
trace which does not reflect the client code line that
failed. Example classes follow.


import java.rmi.*;
import java.rmi.server.*;

public class RemoteStatus extends UnicastRemoteObject implements iStatus
{

    /**
     * Constructor.
     */
    public RemoteStatus ()
throws RemoteException
    {
    }

    public void f2()
throws RemoteException
    {
f3();
    }
    
    public void f3()
throws RemoteException
    {
f4();
    }
    
    public void f4()
throws RemoteException
    {
f5();
    }
    
    public void f5()
throws RemoteException
    {
f6();
    }
    
    public void f6()
throws RemoteException
    {
try
{
f7();
}
catch (Exception e)
{
RemoteException re = new RemoteException("Exception in f7");
re.detail = e;
throw re;
}
    }
    
    public void f7()
    {
f8();
    }
    
    public void f8()
    {
String npe = null;
char[] chars = npe.toCharArray();
    }
}


import java.rmi.*;
import java.rmi.registry.*;

public class StatusServer
{

    /**
     * Constructor.
     */
    public StatusServer ()
    {
    }

    public static void main(String args[])
    {
//Generate a Remote class
//
try
{
System.setSecurityManager(new RMISecurityManager());
System.getProperties().put("java.rmi.server.codebase",
"http://intranet.tridsys.com/~stoddard/");

System.out.println("Creating Server Object");
RemoteStatus status = new RemoteStatus();
LocateRegistry.createRegistry(1099);
System.out.println("Binding RemoteStatus");
Naming.rebind("RemoteStatus", status);
System.out.println("Server is ready");
}
catch (Exception e)
{
e.printStackTrace(System.out);
}
    }
}


import java.rmi.*;

public class StatusTest
{
    static iStatus status;
    static RemoteStatus remoteStatus;

    /**
     * Constructor.
     */
    public StatusTest ()
    {
    }

    public static void main(String args[])
    {
try
{
System.setSecurityManager(new RMISecurityManager());

status = (iStatus)Naming.lookup(
"rmi://192.168.1.133:1099/RemoteStatus");

System.out.println("Server found");

remoteStatus = new RemoteStatus();

//Generate a NullPointerException
//
f1();
}
catch (Exception e)
{
e.printStackTrace(System.out);
}
finally
{
System.exit(0);
}
    }

    
    public static void f1()
    {
try
{
status.f2();
}
catch (RemoteException e)
{
e.fillInStackTrace();
e.printStackTrace(System.out);
}

try
{
remoteStatus.f8();
}
catch (Exception e)
{
e.fillInStackTrace();
e.printStackTrace(System.out);
}
    }
}


import java.rmi.*;

public interface iStatus extends Remote
{
    public void f2() throws RemoteException;
    public void f3() throws RemoteException;
    public void f4() throws RemoteException;
    public void f5() throws RemoteException;
    public void f6() throws RemoteException;
}

When I run the example I get the following output

Server found
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
        java.rmi.RemoteException: Exception in f7; nested exception is:
        java.lang.NullPointerException:
        at StatusTest.f1(StatusTest.java:51)
        at StatusTest.main(StatusTest.java:30)
java.lang.NullPointerException
        at StatusTest.f1(StatusTest.java:61)
        at StatusTest.main(StatusTest.java:30)

At no time does the stack trace report an exception at
line StatusTest.java:47 or StatusTest.java:57, which are
the lines in the try blocks.
(Review ID: 30715)
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