Sun has servlet- and applet-based search engines to download for use with the Java documentation and tutorial. The applet works on Sun's site over the Internet, or on your own local copy of the docs! The applet for the Sun docs is free to download. DocFather, the engine, can be licensed for Internet, Intranet, or CD-ROM Publishing.

I've been meaning to write my own such engine for CD-ROM publishing use. I could put all the docs I ever use on a single, searchable disc... But I've been meaning to write a lot of things.