I have used BEA Web Logic and Sybase EA Server. I can
say that there is a standard way to connect to the
connection pool from Java defined in the J2EE platform,
but some servers dont respect standards, and they have
their own classes for that.

What application server are you using?
What do you want to know about connection  pooling?
What is it?
or how to configure a connection pool?
or how to use it from Java?

You might look at:
orchard.wccnet.org/~chasselb/java278/index.html
Select the Servlets & JDBC button.

I think the best way is to create your own connection  pool (regarding to
experiences...), just look at the
http://jakarta.apache.org/commons/pool/...