Is there a way to query Oracle on the number of connections open (Not as the administrator). I am trying to setup connection pooling and I want something (on the client end) to check how many connections are being maintained etc.

Try find out the number of active connections . Try to use v$session

If your doing the connection pooling at the client end then I'd have thought you'd know how many connections your using.
There are quite a few caching algorithms for various systems around. Depends on what language or in Java - which j2ee engine your using.

We're using Tomcat 5.5. The problem is that I have found at least three different methods for doing it. I don't have a way that I can find of checking the -actual- number of connections being made and when they are being made. I can create different results which tells me a little, such as I can tie up all connections until the max connections and get everything after to fail. Which tells me the JNDI resource is definitely there and working, but I don't know the extent of the 'working'.

My current problem is that I'm trying to make sure a minimum number of connections are being created when the app goes up/tomcat starts. If you know of a way to look at what Tomcat/JNDI is doing and pulling some data on it I would love to know.

Otherwise I need to look at the DB end and see how many sessions that source is maintaining.