Update.
I stopped using Eclipse on Ubuntu for now, but I'm just facing the same problem again, now with Emacs 25.2.1. It appeared when I maximised the window and then tried to reduce it.
gnome-shell CPU load reached 95% and after a while decreased down to 70%, but it's not stable, sometime increases again to some peaks...
Seems not Eclipse related and seems Emacs too can trigger the same troubles.
Please tell me if you need further logs - not sure I can reuse the same reference as above for apport-collect...
Update.
I stopped using Eclipse on Ubuntu for now, but I'm just facing the same problem again, now with Emacs 25.2.1. It appeared when I maximised the window and then tried to reduce it.
gnome-shell CPU load reached 95% and after a while decreased down to 70%, but it's not stable, sometime increases again to some peaks...
Seems not Eclipse related and seems Emacs too can trigger the same troubles.
Please tell me if you need further logs - not sure I can reuse the same reference as above for apport-collect...