I almost didn't notice the exception fly by because there's soooo much log output, and I can see why I might not have noticed. Yay for scrollback! (Hrm, I might not have wanted to watch logging for 4 instances of solr all at once. Might explain why so much logging.)
This has bitten me more then once too! The rationale with the solrconfig stuff is that a broken config should behave as best it can. This is great if you are running a real site with people actively using it - it is a pain in the ass if you are getting started and don't notice errors. I'd like to see a "strict" configuration parameter. If something fails on startup, nothing would work until it was fixed. If there is any interest, I can put this together. The other one that can confuse you is if you add documents with fields that are undefined - rather then getting an error, solr adds the fields that are defined (it may print out an exception somewhere, but i've never noticed it)
Another helpful modification would be returning 500 errors codes in the header. ...
The 'new' RequestHandler framework (apache-solr-1.2-dev) returns a proper response code (400,500,etc). It is not (yet) the default handler for /select, but I hope it gets to be soon. best ryan