Exception on Reflection while running examples about fn-fx HOT 1 OPEN

Script started on Sat Oct 13 12:08:47 2018
bash-3.2$ java -version
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)
bash-3.2$ lein do version, deps, repl
Leiningen 2.8.1 on Java 11 OpenJDK 64-Bit Server VM
nREPL server started on port 61325 on host 127.0.0.1 - nrepl://127.0.0.1:61325
REPL-y 0.3.7, nREPL 0.2.12
Clojure 1.9.0
OpenJDK 64-Bit Server VM 11+28
    Docs: (doc function-name-here)
          (find-doc "part-of-name-here")
  Source: (source function-name-here)
 Javadoc: (javadoc java-object-or-class-here)
    Exit: Control+D or (exit) or (quit)
 Results: Stored in vars *1, *2, *3, an exception in *e

user=> (require '[getting-started.01-hello-word])
nil
user=> ; at this point a window appears, containing a single "Say 'Hello World'" button

user=> ; I click the button:

user=> Received Event:  {:say Hello World!, :fn-fx/includes {}}


user=> exit
Bye for now!
bash-3.2$ exit
exit
Script done on Sat Oct 13 12:10:00 2018