Where is the JDBC Driver for PostgreSQL on Redhat6.0?

Hello

I'm new to Linux. And I want to try some java program on Linux which will
access some database using JDBC.
After I installed redhat6.0 I found there is alread a DBMS PostgreSQL 6.4.2.
So I decided to use this one.

I read the document of the PostgreSQL ( in /usr/doc/postgres6.4.2/). It says
there is already a JDBC driver for PostgreSQL. But in that document it just
teaches u how to build the Driver file (postgresql.jar) from some source
files. But I can find none of them. So I guess maybe when installing Redhat
it didn't install all the files of PostgreSQL, and so u won't have the JDBC
driver? Is it true?

So do I need to download a JDBC driver for it or just download another newer
version of PostgreSQL and re-install it? Or does it just exist somewhere I
don't know?

Thanks in advance!
With my best regards:
Janet