Question about JNI and RMI-IIOP

[Steven Colley]

Hy folks, I have a Legacy connectivity question for you.....

Please take a look at this question :

"You're working for a company that has yet to realize the full potential of Java. You offer to show them some of
the great things Java can do by integrating a new application with an existing CORBA system. Your bosses will then
assess the performance and realibity of this new system. How will you connect your RMI application to the CORBA system."

A. Java IDL.

B. This is a standart feature of RMI.

C. It can't be done.

D. It can only be done by using JNI.

E. User RMI-IIOP.


The mock tool says that the correct answer is option "A".

I'm wondering if the suited answer wouldn't be option E, since the question is : "How will you connect your RMI application to the CORBA system.".

So in my understanding I should assume that a RMI application already exists (or we are going to create that based on RMI to be shown) and you just need to connect it to CORBA. So why should I use Java IDL if I already have an application based on RMI and I could be using RMI-IIOP rather than Java IDL??


Please advice!!

Tks so muuuch!!

[chris zielinski]

Here was the rule of thumb that I used:

Java client talking to a CORBA server: use Java IDL
CORBA client talking to a RMI server: use RMI-IIOP

In the question the aim is for a RMI app to talk to a CORBA service, in which case Java IDL is the available option. The fact that the client program is RMI is not as important as the fact that the client program is Java based.

Also since the server is CORBA based and not necessarily java based, you cannot use RMI-IIOP. RMI can be used only if all parties are java based. RMI-IIOP is for a java service to be backwards compatible with a CORBA client.

It is also worth mentioning that the default protocol for RMI communication is RMI-JRMP not RMI-IIOP. If there is no need to support CORBA clients, it is recommended to use RMI-JRMP.