the problem with jsp is that there aren't that many free host out there where you can try your jsp in the real 'internet' world. mycgiserver is the only one i know that's free. this could be one reason you dont see many jsp websites out there.
with jsp you are practically stuck with testing your site within your home computer and if your lucky your own intranet.
compare this with asp and php, there are numerous free webhosts for them.
right now im testing my tomcat webserver but my problem is my dsl supports dynamic ips. however i tested it and it seems to be working and can be accessed from the internet but problems arise when i disconnect and reconnect to my isp. i get a new ip