Hi Dimitry,
Juste bought GanttProject and unfortunately I do not succeed to launch it.
I am in Version bêta 10.14.4 (18E194d)
The icon bump and close.
I have tried to follow Terminal instructions you gave but with no success.
Could you please help me?
Regards.
Flo
Please elaborate on that. What did you try and what did you get?
At the end, I upload JDK JAVA and everything works fine. 
Thanks Dmitry.
Regards.
Flo
I uploaded JDK but it didn’t work yet.
Eduardo
Closing this discussion because it provides misleading information noise.
Instructions for macOS issues troubleshooting are given on this page: