i haven't reviewed the technical merits of hte patch, but on the subject of the idea...
In general i agree with ian/otis: functionality like this could very easily be abused/missued by novice users who may not realize that more robust solutions may be out there and can be just as easy to setup. That said: any code that does what it's documentation says it does is going to be use to someone.
my concern with the patch as written is that it doesn't have any documentation explaining what it does, or what the caveats are to useing it (ie: how it behaves in failure cases, what approach it takes to blanacing load, etc...) so it won't be clear to people when/if it fits their use cases.
The "Hits" class in Lucene-Java is a great example of code whose existence tended to do more harm then good – it was a simple API that was easy to use, but the implementation had a lot of "gotchas" that were hidden behind a black box and were too complicated to document cleanly for novice users; many people who used it ran into performance problems or problemswith closed IndexSearchers and came away with a bad impression of Lucene. ... we just need to make sure we don't make more mistakes like that with convinienceclasses and "simple" APIs for hard problems.
If the behavior of this class can be documented in a straight forward way (spelling out both success and failure cases) as well as when it doesn't make sense to use it, then i see no reason not to commit. (I'm assuming of course that the code actually works)
I'm curious as to whether or not anyone has done any research into existing java libraries that implement http load balancing. (I assume someone somewhere has implemented a generic wrapper/plugin for HttpCLient that does this already ... it's just a question of if it's OpenSource with a freindly liscence for us to link against)