Basic question about versions used in an ear

[Julien Martin]

Hello,

Can I have the following architecture in an ear file?

-one ejb module (ejb version 2.1)
-one ejb module (ejb version 3.0)
-one war module (jsp version 2.1, servlet version 2.5)
-one war module (jsp version 2.0, servlet version 2.4)

If so, which can communicate with which?

Thanks in advance,

Julien.

[Jeanne Boyarsky]

Julien,
I'm not positive, but I think the EAR has to use the same version of J2EE.

Any module in the same EAR can communicate with the others. So if you able to have different versions of components, they can communicate.

[Jeroen T Wenting]

For the EJB modules I don't know, but you can put in web modules responding to an earlier version of the spec because those are fully backwards compatible.
But why would you? The only thing you need to do is change a single line in the header of the web.xml for the webcomponent to bring it up to date (and maybe change the way you define your JSTL descriptor if you're using a really old version now).