Open Source Search Engines in Java

Zilverline is what you could call a 'Reverse Search Engine'. It indexes documents from your local disks (and UNC path style network disks), and allows you to search through them locally or if you're away from your machine, through a webserver on your machine. Zilverline supports collections. A collection is a set of files and directories in a directory. PDF, Word, txt, java, CHM and HTML is supported, as well as zip and rar files. A collection can be indexed, and searched. The results of the search can be retrieved from local disk or remotely, if you run a webserver on your machine. Files inside zip, rar and chm files are extracted, indexed and can be cached. The cache can be mapped to sit behind your webserver as well.