LogCrawler is an ANT task for automatic testing of web applications. Using a HTTP crawler it visits all pages of a website and checks the server logfiles for errors. Use it as a "smoketest" with your CI system like CruiseControl.
Provide a plugabble and configurable alternative to UNIX tools like grep, awk, tail, head, cut, sort, uniq or even some perl based scripts in a Java environment. A bit like what ApacheAnt means to good old make.