I'm trying to integrate searchable help into my Java (Swing) application. I'm using docbook right now to generate pdf help, and I know it can generate JavaHelp. I think the default viewer for JavaHelp is rather unappealing though (especially on windows, even when using the windows L&F). I couldn't find any nice looking viewers, but curious if you know of any out there, or if there are better alternatives for help within the application.
The default content viewer (HTML renderer) in JavaHelp is HTMLEditorKit. This component is not very impressive; it only supports HTML 3.2 and has limited CSS capabilities. It is possible to plug in alternative content viewers in JavaHelp.
You might want to try Oracle Help. It is very similar to JavaHelp, but more actively maintained. The default content viewer that comes with Oracle Help is also more capable. The DocBook-XSL JavaHelp stylesheets may require some tweaking in order to produce output that works with Oracle Help (see this page).
It is hard to find definitive information about status and future plans for these technologies. JavaHelp had its latest release in October 2007, while Oracle Help 11.1.2.1.0 was released in September 2011. There are forums (here and here), but the activity is low.
Perhaps you'd be interested in a web/browser-based help system. In that case take a look at WebHelp, one of the newer output formats for DocBook content.