stress test

Dear Sir/Madam,
      One of our customers asked me to do stress test with postgresql
database server but i don`t know what to do i am new bie to postgresql.
I asked my co-worker he said do stress using java servlet with postgresql!
I couldn`t understand please let me know if any one knows!
  I have installed postgresql 7.2,servlet engine(tomcat),I had executed many
database programs in servlet with postgresql.
     Please any one give me idea for doing stress test in postgresql with
servlet
   bye
     kumar