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Author Narrow returns null
Christian Naeger

2006-02-10, 7:57 am

Hi all,

I desperately need your help.

I have written a simple Statless Session Bean and successfully deployed
it to Sun App Server 8.2. Moreover, I have written a small Java
application (a standalone application, with the jar from amin
get-client-stubs on the classpath) that looks up the Session Bean. The
look up is successful and I get an object of the correct type. The
narrowing does not throw an exception but unfortunately it does return
a null pointer. Please, have a look at the client code and the output
below.

I have tried everything I can think of and I believe I have done
everything correctly. Yet, it just doesn't work. Could anyone please
give a hint what I am probably doing wrong (the API does not mention
narrow returning null and google didn't bring up a solution either)?

Any help is greatly appreciated.
Greetings, Chris

Client-Code:
=========

Hashtable props = new Hashtable();
props.put("java.naming.factory.initial",
"com.sun.jndi.cosnaming.CNCtxFactory");
props.put("java.naming.provider.url", "iiop://localhost:3700");
Context ic = new InitialContext(props);
Object o = ic.lookup("ejb/BankMgr");
if (o == null)
System.out.println("Null Pointer");
else
System.out.println("No Null Pointer");
System.out.println(o.getClass().getName());
System.out.println(o.toString());
System.out.println(BankMgrHome.class);
o = PortableRemoteObject.narrow(o, BankMgrHome.class);
if (o == null)
System.out.println("Null Pointer");
else
System.out.println("No Null Pointer");



Output:
=======

No Null Pointer
com.sun.corba.se.impl.corba.CORBAObjectImpl
IOR:000000000000002f524d493a6e696e762e65
6e7469746965732e42616e6b4d6772486f6d653a
3030303030303030303030303030303000000000
00010000000000000178000102000000000a3132
372e302e302e31000e7400000056afabcb000000
00260000003f00000009533141532d4f52420000
000000000002000
00008526f6f74504f41000000001237343637393
631373538323037313830380000000000000d010
950b76df1000000000001ff14000000000007000
0000100000020000000000001000100000002050
1000100010020000101090000000100010100000
0002600000002000200000000000300000014000
000000000000a31
32372e302e302e31000eec000000030000001400
0000000000000a3132372e302e302e31000f5000
00001f0000000400000003000000200000000400
0000010000002100000078000000000000000100
000000000000240000001c000000660000000000
0000010000000a3132372e302e302e31000eec00
400000000000080
6066781020101010000001704010008060667810
20101010000000764656661756c7400040000000
0000000000000010000000806066781020101010
000000f
interface ninv.entities.BankMgrHome
Null Pointer

Jeffrey Spoon

2006-02-11, 6:58 pm

In message <1139571182.914864.130020@g14g2000cwa.googlegroups.com>,
Christian Naeger <naeger@gmx.de> writes
>


>
>Any help is greatly appreciated.
>Greetings, Chris
>
>Client-Code:
>=========
>
> Hashtable props = new Hashtable();
> props.put("java.naming.factory.initial",
> "com.sun.jndi.cosnaming.CNCtxFactory");
> props.put("java.naming.provider.url", "iiop://localhost:3700");
> Context ic = new InitialContext(props);
> Object o = ic.lookup("ejb/BankMgr");
> if (o == null)
> System.out.println("Null Pointer");
> else
> System.out.println("No Null Pointer");
> System.out.println(o.getClass().getName());
> System.out.println(o.toString());
> System.out.println(BankMgrHome.class);
> o = PortableRemoteObject.narrow(o, BankMgrHome.class);
> if (o == null)
> System.out.println("Null Pointer");
> else
> System.out.println("No Null Pointer");
>
>
>


This is going to be no help whatsoever, but why do you use == to test
the equality of Object o? If you use if(o.equals(null)) you'll get a
null pointer exception.



--
Jeffrey Spoon

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