DD elements for JNDI

[Joe San]

Guys,

The following question is from the HFSJ book,

Which are the DD elements that provide JNDI access to J2EE components?

<ejb-ref>
<entity-ref>
<resource-ref>
<session-ref>
<message-ref>

I choose <ejb-ref> but the answer says both <ejb-ref> and <resource-ref>?

Is the <resource-ref> optional element? and if yes, then why not it was stated anywhere in the HFSJ book?

[Christophe Verré]

Is the <resource-ref> optional element?

Yes, it's optional.

and if yes, then why not it was stated anywhere in the HFSJ book?

Maybe because the authors thought that it was not part of the exam I don't know if it actually is.

[Joe San]

Thanks Christophe...