Globaldocs allows you to conveniently browse multiple Javadoc sets
simultaneously, using a single packages/classes hierarchy tree and a
searchable index. It supports local and remote docsets, including the
local docsets, packed as JAR/ZIP-files.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
Yet another way to add a new docset to the configuration was added: open a new docset in the viewer window (all the frames should be visible in the window) and then click the green plus button. There are some bugfixes and code cleanup.