Not able to connect to postgresql database

Hi,

I am a newbie for postgresql. I am trying to connect to postgresql database
using jdbc. I googled about it and got the Driver string and connection
string formats. I tried using some examples i got on the internet. But my
program is not able to connect to postgresql and shows an exception that it
cannot find driver. I am doing it in Ubuntu8.04 Linux with Postgresql 8.3
installed. I am using Eclipse galileo as IDE. I created database using
commands in terminal. I have added the external jar files for postgresql
jdbc connector(postgresql-8.3-603.jdbc3.jar, postgresql-8.3-603.jdbc4.jar,
postgresql-8.4-701.jdbc3.jar and postgresql-8.4-701.jdbc4.jar) in my project
also.

Please help me and let me know what i am doing wrong and what i am missing.
Can you please give an example code if possible?

Thanks
--
Regards,
Manohar Bhattarai (मनोहर भट्टराई)
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