I have just discovered that Eclipse supports Hippie Completion.  It’s a
strange name that dates back to emacs (where it first appeared) and it’s also
supported in IDEA.  The default key binding in Eclipse is ALT-/ and it’s
become my new best friend.

Hippie Completion tries to complete immediately (as opposed to offering you
suggestions, which is what happens when you type Ctrl-Space) based on what you typed recently and the surrounding context. 
It’s a bit hard to describe and actually, there doesn’t seem to be any
documentation about it except for the initial
request for
enhancement
, which was implemented by an external contributor and promptly
integrated into Eclipse.

What matters to me is that 90% of the time, it inserts the right symbol.

Try it, you’ll get hooked.

Update:  Alexandru asked me how I found out, it’s simple: Ctrl-Shift-l
(that’s an "l" as in "little"), which displays the little window you can see at the
top of this article, and which lists all the key bindings available in the
current context.  Great way to make discoveries.