A fellow developer dislikes the Eclipse hovering Javadoc and would like to disable it (one option), or, better yet, only selectively enable it (other option). He\'s using Eclip
Not sure what you mean by "selectively" enabling it. Based on what?
Directions below are for 3.5, I don't have 3.3 lying around to check but I'm pretty sure same settings were available.
Go to Window - Preferences; select Java -> Editor -> Hovers on left hand side. You'll have to uncheck the Combined Hover option on the right; you can then either uncheck Javadoc option or check it but specify a modifier key for it (in the edit box below). In the latter case javadoc hover would only appear if you hold that key.
I've got to say, though, that the inconvenience of not having Combined Handler makes this really not worth it in my opinion.
You could go to
Preferences / Java / Editor / Hover
and untick the "Combined Hover" option: no more popup.
Then you would have:
Shift+F2: open the external javadoc if javadoc archive or directory has been associated with your project (and if some javadoc has been generated)
Alt+Shift+Q, followed by J: open the javadoc view, with the same content than the popup previously seen on mouse hovering.
In Eclipse 3.6 you can now specify a modifier key to be pressed down for the Combined Hover to be activated. This way, you can have the old behavior without the automatic popups. The automatic popups were driving me crazy, often obscuring something I was trying to read.