Comment 3 for bug 563181

not sure if this is going to help anyone, but I managed to make my bug disappear entirely
I'm not exactly sure what fixed it; eclipse was crashing as I cycled through different java vm's in eclipse startup command. Then, I began to suspect that this bug was an issue with Mozilla (due to the libmozjs in log output). I think the only relevant changes I made to my system at this point was to add the mozilla ppa and run apt update/upgrade. I didn't see any eclipse-related packages in my list of packages ready for upgrade (I only recall seeing mozilla stuff, as I had already updated/upgraded less than an hour before).
Then, I started eclipse again. As I had been doing, I pressed ctrl+space as soon as eclipse finished setting up the workspace. Instead of crashing like I expected, a dialog box popped up telling me that my content assist settings had been changed.

The program now works perfectly as far as I can see.