error XDG_RUNTIME_DIR not set in the environment.

When I start matlab from a linux console I get this error

XDG_RUNTIME_DIR not set in the environment.

I wonder if it has anything to do with the graphics crashing very often.

I am using matlab 2018b un Ubuntu 18.04

[Walter Roberson]

Some information about XDG_RUNTIME_DIR at https://askubuntu.com/questions/872792/what-is-xdg-runtime-dir