Flooring always goes last. You don't want to damage a new floor or any OOPS. Even covering the floor, one grain of dirt can scratch it up.
Should be done at same time. New flooring first so it can go under cabinets and not mess with level changes for dishwasher and height of cabinets to range height. Plus you may change the footprint of your cabinets.
New flooring should go under the cabinets for a cleaner, more professional look.
I did the floor first so it be could under the cabinets, dishwasher, and oven.
floor first ... various reasons .... but it's the mess --- and you'll be sure the sub floor is sound ... and not have to remove! a new cabinet in order to repair the subfloor!
Do the floor last. You may get scratches/dings on the new floor while installing or upgrading the cabinets.
The floor typically goes in before the cabinets. A couple of reasons for this are the flooring will add height to the floor, thus if installed after cabinets will lessen the toekick area of the cabinets. The floor is easier to install without having to cut around the cabinets. If floor goes in after, then you'll need to add a shoe moulding to cover the crack under the cabinets. And the list goes on... Once the floor is installed, it's a good idea to cover it with builder's paper, taping the seams of the paper, going wall to wall. That will help protect it. Also, frequently a wood floor install is given the final finish coat after everything else is done. Here's a link to my DIY & decorating blog, Simple Decorating Tips that shows my son and daughter-in-law's kitchen that was renovated. Amazing before to after difference!