Stop spacebar keypress from triggering autocomplete in Eclipse

Question

_Update

_{This was fixed in Eclipse 2018-12. This behaviour is still default, but can be configured off - see the accepted answer for how}

_{I'll leave the question as it was for posterity, and for those on earlier versions of Eclipse}

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In Eclipse, I've enabled intellisense-style suggestions for Java by going to

Window -> Preferences -> Java/Editor/Content Assist 

and setting the following

Auto activation delay (ms) -> 0 Auto activation triggers for Java -> .(abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ 

source = Eclipse Intellisense?

This works brilliantly, apart from one annoying problem. When I hit spacebar, the token being typed is autocompleted with whatever is at the top of the suggestions list. Fair enough, except that sometimes I'll type a class/variable name with an exact legal match, but this won't appear as the top suggestion. So when I naturally hit spacebar Eclipse inserts something completely wrong.

E.G. after typing Cookie I'll hit spacebar and get CookieMonster.

This seems like a bug, and happens often enough to be annoying, but even despite this I don't want spacebar to trigger autocomplete in general. I may want to type a variable name which hasn't been declared yet, or something similar. I want to use autocomplete as a helper tool, but my natural typing should always take priority over it.

I'd like to stop spacebar triggering autocomplete, and either fall back to using enter, or better still trigger autocomplete with a custom key not used in ordinary typing. Is any of this possible?

I've played around with all the settings in Content Assist to no avail. Googling the question just returns a bunch of results about disabling the autocomplete feature.

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This issue is fixed from Eclipse 2018-12 [4.10] see the accepted answer

It's present in all prior versions, i.e. 2018-09 [4.9], Photon [4.8], Oxygen [4.7], Neon [4.6], etc..

Answer 1

Eclipse 2018-12 was already patched for this!

A patch for Bug 348857 was recently merged to the Eclipse project and was released as part of Eclipse 2018-12. You can download that version here.

You now have a new option to disable all insertion triggers apart from enter, which will prevent spacebar from causing autocompletion.

Simply go to Preferences... -> Java -> Editor -> Content Assist (or Window -> Preferences -> Java -> Editor -> Content Assist on Windows) and select Disable insertion triggers except 'Enter', as shown in the screenshot below: