I'm newbie in J2EE, having read a bunch of stuff I'm still in the wood. Please bear with me.

Here's an example descriptor:

<ejb-jar>
 <enterprise-beans>
 <session>
 <ejb-name>beanA</ejb-name>
 ...
 <resource-ref>
 <res-ref-name>jdbc/dbname</res-ref-name>
 <jndi-name>jdbc/dbname</jndi-name>
 <res-type>javax.sql.DataSource</res-type>
 <res-auth>Container</res-auth>
 <res-sharing-scope>Shareable</res-sharing-scope>
 </resource-ref>

 <env-entry>
 <env-entry-name>Var1</env-entry-name>
 <env-entry-type>java.lang.String</env-entry-type>
 <env-entry-value>Some value</env-entry-value>
 </env-entry>
 ...


 <ejb-ref>
 <ejb-ref-name>ejb/ses1</ejb-ref-name> QUESTION 1: ejb/ses1??? Is it "SS1" JNDI name? Why isn't JNDI name declared in "ejb-jar.xml"??
 <ejb-ref-type>session</ejb-ref-type>
 <home>tests.SS1Home</home>
 <remote>tests.SS1</remote>
 </ejb-ref>

 <ejb-local-ref>
 <ejb-ref-name>ejb/locses1</ejb-ref-name>
 <ejb-ref-type>session</ejb-ref-type>
 <local-home>tests.LocalSS1Home</local-home>
 <local>tests.LocalSS1</local>
 </ejb-local-ref>
 ...

 </session>

 <session>
 <ejb-name>SS1</ejb-name>
 <home>tests.SS1Home</home>
 <local-home>tests.LocalSS1Home</local-home>
 <remote>tests.SS1</remote>
 <local>tests.LocalSS1</local>
 <ejb-class>tests.SS1Bean</ejb-class>
 ...
 </session>
 ...
 </enterprise-beans>
</ejb-jar>

QUESTION 2. What's the purpose of "ejb-ref", "ejb-local-ref" in EJB deployment descriptor? Is it that if one EJB (ejb/beanA) depends on another, say (ejb/ses1) (by virtue of having the dependency declared in deployment descriptor) - deployment of "ejb/beanA" would fail if "ejb/ses1" was not deployed on the target server? That DEPLOYMENT of an EJB (depending on a particular resource) would FAIL if that resource it depends on is absent on the destination server? Is this the only purpose?

QUESTION 3. Should I specify JNDI names for <ejb-name> tag?

QUESTION 4. Is "fully qualified" JNDI name (for the above bean):
JNDI name = "java:comp/" + <ejb-name>
example: "java:comp/ejb/beanA"

OR just:
JNDI name = "java:" + <ejb-name>
example: "java:ejb/beanA"

Is this true for all application servers? JBoss? Or does it depends on "ejb-name" to "jndi-name" mapping as specified in "jboss.xml" (see below)

QUESTION 5. For JBoss EJB's, "ejb-name" to "jndi-name" mapping is done in "jboss.xml":

<jboss>
 <enterprise-beans>
 <entity>
 <ejb-name>beanB</ejb-name>
 <local-jndi-name>ejb/beanB</local-jndi-name>
 </entity>
 <session>
 <ejb-name>beanA</ejb-name>
 <jndi-name>ejb/beanA</jndi-name>
 </session>
 </enterprise-beans>
</jboss>

Does it mean if "jndi-name" is NOT specified, then by default, "jndi-name" of the bean would equal "ejb-name"?

"java:com/" + <ebj-name>

EQUALS:

"java:com/" + <jndi-name>

EQUALS:

"java:com/beanA"


QUESTION 6. Why "java:comp/"? What's that for? Is it:
a. "java:comp/"
b. "java:comp"
c. "java:"

I think I've seen different versions, getting really confused.

QUESTION 7. For environment variables, it seems:

JNDI name="java:comp/env" +<env-entry-name>

In this case,
"java:comp/env/Var1"

Is this true for all servers?

QUESTION 8. For data sources (JBoss), you need to put "mysql-ds.xml" under "Deploy" folder:

<datasources>
 <local-tx-datasource>
 <jndi-name>jdbc/exampleDS</jndi-name> <connection-url>jdbc:mysql://127.0.0.1:3306/DBName</connection-url>
 <driver-class>...</driver-class>
 <user-name>xxx</user-name>
 <password>xxx</password>
 </local-tx-datasource>
</datasources>

6a. I dont understand why we need to append "java:" in context.lookup:

context=new InitialContext();
dataSource=(DataSource) context.lookup("java:jdbc/exampleDS");

6b. Can we rename the file name "mysql-ds.xml" to anything we like as long as it remains in "Deploy" folder? (Tested this on JBoss)

Thanks.