I have tried with a fresh curl install of Processing on a current Raspberry Pi Stretch.
The examples are running well inside the processing GUI*, but when I export the examples (e.g.MixtureGrid), I get 4 folders and in the folder
application.linux-armv6hf
the sh file upon a double click asks to execute or execute in terminal.
If you chose execute it will do nothing visible
If you chose execute in terminal it will open an error Failed to execute child process xterm (no such file or directory)
Additional info: I am running VNC.
Running within the IDE, the MixtureGrid example is displayed on the HDMI screen, but NOT on VNC, which shows only a black window.
The compiled MixtureGrid misbehaves identically if I control it from a Keyboard/mouse/Scrren or over VNC.
P.S. I compiled without the JAVA libraries since I have Oracle JAVA8 installed already.