Pier Fumagalli, over at the Cocoon developer’s wiki, explains using Apache’s built-in proxy, instead of additional modules, to wire your servlet engine into your primary web server. Since this stuff works right out of the box, it’s a worthy subsitute for mod_jk, mod_webapp, etc.
I was turned on to this a couple weeks back when, by chance, I met one of the Apache developers while hanging out at the free wifi, er, coffee house, down the street from my place in Mountain View.
Given the ease of mod_proxy, why use anything else? Really, if I’m missing something, set me on the path of righteousness via a trackback.
By the way, I’ve found the Cocoon Wiki to be a great resource. I’m putting my notes on understanding Lenya CMS up there as I write them.