BARNARDEEP  finally got it to work. for those who still can't get it to work, edit the file ~/Library/Preferences/ch.seriot.widget.JavaDoc.plist

using text edit

and change this part

searchPaths

...

/Users/nst/my_doc_path/

where it says nst i put my user log in name for my mac and the doc path i changed to my folder where i downloaded the java api from java.sun.com. took me a good few tries and a visit to http://seriot.ch/JavaDoc to figure it out.  
(Version 0.7)