The shortcut keys are still available (listed by the ? icon).
Justify = Shift + Alt + j
Underline = Ctrl + u
The somewhat ridiculous explanation for loss of the tools is at:-
I am quite sure they are trying to herd us into the new Editor as part of their move to all Application Programming Interface (API).
A forum topic about the New Editor (do pitch in) is at:-
If they would only replicate the original facilities then there wouldn’t be a problem. They don’t seem capable.
Meanwhile more and more blogs are being abandoned.
Update: Having examined 298 blogs of those following me or being followed by me since May 2014, 36% have ceased to function:-
2 % stopped functioning in 2014.
8 % stopped functioning in 2015.
16 % stopped functioning in 2016 (last post being before November) .
6 % have been deleted by authors or have no server.
2 % have no content.
2 % ceased to exist.
More About WP Changes ⇐.