Hi Mamadou,
i'll try to answer some questions:
1 - Do we still need this file (ejb-jar.xm) in a ejb application ?
Here is excerpt from Mikalai Zaikins Study Guide:
The ejb-jar file must contain the deployment descriptor (if any) in the format defined in the Deployment Descriptor XML Schema. The deployment descriptor must be stored with the name META-INF/ejb-jar.xml in the ejb-jar file.
NOTE: The biggest difference with EJB 2.0 is that with the EJB 3.0 release the deployment
descriptor becomes optional.
2- If so, is it the container that translates the entries from the ejb-jar.xml to jndi entry automatically ?
If there exists a ejb-jar.xml file, then I think that it is the responsibility of the container to read in this file, override annotations and so to create jndi entries.