When I last tried to get the JDEE running on Windows with GNU Emacs 22 I was stung by the old inaccuracy in the installaiton guide concerning the installation of the cedet.

The guide suggests you add the different needed parts of the cedet separately by doing this:

(add-to-list 'load-path (expand-file-name "~/emacs/site/jde/lisp"))
(add-to-list 'load-path (expand-file-name "~/emacs/site/cedet/common"))
(load-file (expand-file-name "~/emacs/site/cedet/common/cedet.el"))
(add-to-list 'load-path (expand-file-name "~/emacs/site/elib"))

This kept on giving me errors and after trying various versions of the cedet libraries it dawned on me that it might just be possible to load the cedet as a whole, which it was. I did it like this:

(add-to-list 'load-path (expand-file-name "C:/elisp/cedet-1.0pre3/common"))
(require 'cedet)

It now works like a charm and I thought I might as well share it, maybe you'll get hit by the same problem one day (or I'll forget about it again ).

For completeness sake, this is the full code in my .emacs for loading the JDE on Windows (it's the same for other OSs, just substitute the correct paths):

;;; JDEE
(add-to-list 'load-path (expand-file-name "C:/elisp/elib-1.0/"))
(add-to-list 'load-path (expand-file-name "C:/elisp/cedet-1.0pre3/common"))
(add-to-list 'load-path (expand-file-name "C:/elisp/jde-2.3.5.1/lisp/"))
(require 'cedet)

;; (require 'jde)
(setq defer-loading-jde t)

(if defer-loading-jde
    (progn
      (autoload 'jde-mode "jde" "JDE mode." t)
      (setq auto-mode-alist
        (append
         '((".java'" . jde-mode))
         auto-mode-alist)))

(require 'jde))