Otherwise ... good news: Not sure, if you have stumbled over this, but if you try to make your method completion work you might get an error message along the lines of ...
Cannot find JDK's tools jar file (or equivalent). Type M-x describe-function [RET] jde-get-jdk-dir for more info.
... when you hit C-c C-v . to complete a method name. The problem is that the beanshell cannot find tools.jar (or more specifically classes.jar (on MacOS)).
In my case my jde-get-jdk-dir returns ...
... but if you look the error message up in ...
~/Library/Application Support/Aquamacs Emacs/jdee-126.96.36.199/lisp/jde.el
... you will see that on the darwin platform (MacOS) it tries to find the classes.jar file (which contains the tools stuff on darwin) in Classes/classes.jar, but the correct location is ../Classes/classes.jar, means to make it work you have to change jde-get-tools-jar() in jde.el to ...
(defun jde-get-tools-jar ()
"Gets the correct tools.jar or equivalent. Signals an
error if it cannot find the jar."
(if (eq system-type 'darwin)
(if (file-exists-p tools)
(error (concat "Cannot find JDK's tools jar file (or equivalent)."
"Type M-x describe-function [RET] jde-get-jdk-dir for more info.")))))
... and then byte-compile it (just go to the Emacs-Lisp menu and select "Byte-compile this File"). Last but not least, you need to restart AquaEmacs and you are done.
OK. I admit it ... this is nerdy :).