Context/JNDI Problems

[Rick Mann <rm...@latencyzero.com>]

As I was composing this email, I solved the problem. However, I don't 
understand why to problem occurred. Two things are happening.

1) I (mistakenly?) configured my Context path to be "store" (no 
preceding slash) rather than "/store". This makes the difference, in 
that "/store" has correctly-behaving JNDI. But what is the difference as 
far as Tomcat is concerned? How does Tomcat interpret these two 
differently?

2) In the broken "store" configuration, I get the behavior described 
below. In a nutshell, I can see that "java:comp/env/jdbc/store" exists 
in the tree, but if I try to look it up directly, I get the exception 
below. If the app is deployed under "/store", everything is fine. What 
gives?

Instinctively, I would feel better if I could turn off the 
auto-deployment of webapp directories in Tomcat. Is there a way to do 
this?

----------------------------------------------

I recently moved code running on Mac OS X 10.1.5/Java 1.3.1/Tomcat 
4.0.4b3 to RH7.2/Java 1.4.0_01/Tomcat 4.0.4. One of the most basic 
things I do is get a DataSource from JNDI. On the new installation, this 
fails.

I wrote a little Servlet to return the JNDI java:comp tree. Part of its 
output is:

> java:comp really does indeed contain:
>
> *	"UserTransaction" (java:comp): "org.apache.naming.TransactionRef" 
> (org.apache.naming.TransactionRef)
> *	"env" (java:comp): "org.apache.naming.NamingContext" 
> (org.apache.naming.NamingContext)
> *	"jdbc" (env): "org.apache.naming.NamingContext" 
> (org.apache.naming.NamingContext)
> *	"store" (jdbc): "org.apache.naming.ResourceEnvRef" 
> (org.apache.naming.ResourceEnvRef)

You can see that there is something under "java:comp/env/jdbc/store". 
However, executing the following code results in a 
"javax.naming.NamingException: Cannot create resource instance" 
exception.

> 	Context c = (Context) context.lookup("java:comp/env/jdbc");
> 	if (c != null)
> 	{
> 		out.println("Found jdbc: ");
> 		Object o = c.lookup("store"); // <--- exception here
> 		if (o != null)
> 		{
> 			out.println("Found store: " + o.getClass().getName());
> 		}
> 		else
> 		{
> 			out.println("Could not find store");
> 		}
> 	}

The server.xml files for the two machines were set up the same, with the 
exception that on the working Mac OS X installation, the Context was 
based at the doc root, and placed in webapps/ROOT. On the RH7.2 machine 
that fails, the Context was based under "store"...


...fixed.


--Rick


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