HFEJB: What the difference between pass object as copy and as reference?

[John Anaivs]

Hi, I saw this in the HFEJB page 69 and I would like to know if somebody may give me some help. Thanks, Nato.

[Rahul Mishra]

Hi Nato,

Look at the accompnying pictures. Never understimate the power of those pictures in the books of Head First Series.

The pictures where they talk of a Dog Reference.
Just when you thought they dont make any sense , they will, have a look again and come back.

If you are still stuck, the ranchers will surely help you

But as 'Head First' says...when you devour the problem yourself..you understand the concept best

[John Anaivs]

Hi Rahul, thanks for your reply. I didn't understimate the pictures. I just didn't undestood in this context.. But I think I did understimate my Java knowledge. I'm a SCJP 1.4 and I know the Java concepts. I just think that I became a little scared with this concepts together with RMI. Thanks again, Nato.

[Rahul Mishra]

Well,

Happens to all of us..and most of all me

In terms of EJB ( when it uses RMI - IIOP/ RMI) objects are passed by Value but you already know that in Java objects are passed by Reference.

Now you would say why this difference?

Primarily because, when i say RMI ...i say across the network..i mean different JVM's ...right???

A reference in one JVM doesnt mean anything in another...so you cant pass it by reference...(unless..there is a concept of a remote object itself being passed which you can explore later..thats pass by reference even in RMI)...so the other option is pass by Value...

Hope this rudimentary info helps...Rest...HFEJB explains this concept in detail...

[John Anaivs]

Thanks Rahul, it's helped so much.

[Rahul Mishra]

Thats what we do here..help each other