related to SOLR-203 and rev:535580. Some servlet containers (including resin) use an empty string as the getServletPath() if you are on the webapp root: http://localhost:8983/solr others (jetty) redirect to: http://localhost:8983/solr/ This makes sure it is a real path before trying to match a request handler.
lucene/solr/trunk/src/webapp/src/org/apache/solr/servlet/SolrDispatchFilter.java