A couple links to help with Apache-JK2-Tomcat on Debian
During my recent re-installfest, I searched high and low for JK2 documentation. I could not find any "official" documentation on building JK2 for Debian, but I was able to fumble my way through by following the steps in a Debian mailing list post titled mod_jk and mod_jk2. I tried using the latest version of JK2, which is 2.0.4, but I could not get it to compile. I ended up using version 2.0.2. I'm using Debian testing, by the way.
Once I had built JK2, I followed the JK2 documentation on the Jakarta website. I was able to get JK2 working, but I kept getting intermittent HTTP 500 errors from the server. I started looking for alternative ways to configure JK2. I found some very helpful instructions at Greenfield Research titled Tomcat-Apache using JK2 Connector. I followed those instructions and I haven't seen a 500 since.